Pub Date : 2024-10-25DOI: 10.1016/j.checat.2024.101163
Cheng Zhang, Shanliang Dong, Martin C. Dietl, Matthias Rudolph, Xinke Zhang, Kemiao Hong, Wei Yi, A. Stephen K. Hashmi, Xinfang Xu
The exploration of reactive intermediates, which enable chemo- and regioselective cycloaddition reactions for the expeditious construction of fused and/or bridged ring systems, continues to draw a great deal of interest from the synthetic community. Vinylcarbene species, which serve as 3-carbon building blocks, have been frequently used for the construction of (hetero)cyclic frameworks through the successive formation of multiple carbon–carbon and/or carbon–heteroatom bonds. Herein, we report a concise strategy for the catalytic generation of an exocyclic α-vinyl gold carbene species via a selective gold(I)-promoted azide-enyne cyclization process. Subsequently, practical and modular cycloadditions of these in-situ-formed intermediates with different types of partners were disclosed, producing a diverse array of fused and bridged pyrroles in high chemo-, regio-, and stereoselectivity.
{"title":"Practical and modular cycloadditions of in-situ formed exocyclic vinylcarbenes","authors":"Cheng Zhang, Shanliang Dong, Martin C. Dietl, Matthias Rudolph, Xinke Zhang, Kemiao Hong, Wei Yi, A. Stephen K. Hashmi, Xinfang Xu","doi":"10.1016/j.checat.2024.101163","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101163","url":null,"abstract":"The exploration of reactive intermediates, which enable chemo- and regioselective cycloaddition reactions for the expeditious construction of fused and/or bridged ring systems, continues to draw a great deal of interest from the synthetic community. Vinylcarbene species, which serve as 3-carbon building blocks, have been frequently used for the construction of (hetero)cyclic frameworks through the successive formation of multiple carbon–carbon and/or carbon–heteroatom bonds. Herein, we report a concise strategy for the catalytic generation of an exocyclic α-vinyl gold carbene species via a selective gold(I)-promoted azide-enyne cyclization process. Subsequently, practical and modular cycloadditions of these <em>in</em>-<em>situ</em>-formed intermediates with different types of partners were disclosed, producing a diverse array of fused and bridged pyrroles in high chemo-, regio-, and stereoselectivity.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":"99 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489372","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-25DOI: 10.1016/j.checat.2024.101153
Wenchao Jiang, Chenwei Ni, Yejun Xiao, Yue Zhao, Chu Han, Xuan Wu, Chengbo Zhang, Haibo Chi, Rengui Li, Can Li
Although crystal facet engineering of semiconductor crystals has been demonstrated to be effective in particulate photocatalysts for solar energy conversion, it is imperative to rationally regulate the exposed crystal facets and their configurations to improve charge separation efficiency. In this study, focusing on visible-light-driven water oxidation photocatalyst lead chromate (PbCrO4), we find that a flux-assisted treatment enables the precise tuning of the hole-accumulating facets of anisotropic PbCrO4 crystal, transitioning the top surface from {−101} to {001} facets while preserving its spatial charge separation characteristics. Owing to the superior hole-accumulating property and water oxidation kinetics of the {001} facets, the resulting Flux-PbCrO4 crystals achieve a charge separation efficiency exceeding 75%, leading to a remarkable improvement in photocatalytic water oxidation activity. Further incorporation of cocatalysts onto the Flux-PbCrO4 crystals results in an apparent quantum efficiency of 18.5% at 500 nm for photocatalytic water oxidation.
{"title":"Boosting photocatalytic water oxidation on lead chromate through crystal facet engineering","authors":"Wenchao Jiang, Chenwei Ni, Yejun Xiao, Yue Zhao, Chu Han, Xuan Wu, Chengbo Zhang, Haibo Chi, Rengui Li, Can Li","doi":"10.1016/j.checat.2024.101153","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101153","url":null,"abstract":"Although crystal facet engineering of semiconductor crystals has been demonstrated to be effective in particulate photocatalysts for solar energy conversion, it is imperative to rationally regulate the exposed crystal facets and their configurations to improve charge separation efficiency. In this study, focusing on visible-light-driven water oxidation photocatalyst lead chromate (PbCrO<sub>4</sub>), we find that a flux-assisted treatment enables the precise tuning of the hole-accumulating facets of anisotropic PbCrO<sub>4</sub> crystal, transitioning the top surface from {−101} to {001} facets while preserving its spatial charge separation characteristics. Owing to the superior hole-accumulating property and water oxidation kinetics of the {001} facets, the resulting Flux-PbCrO<sub>4</sub> crystals achieve a charge separation efficiency exceeding 75%, leading to a remarkable improvement in photocatalytic water oxidation activity. Further incorporation of cocatalysts onto the Flux-PbCrO<sub>4</sub> crystals results in an apparent quantum efficiency of 18.5% at 500 nm for photocatalytic water oxidation.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":"6 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.checat.2024.101160
Godwin A. Aleku, Florian Hollfelder
Imine reductases (IREDs) are invaluable catalysts for enantioselective imine reduction and reductive amination of carbonyl compounds. Their synthetic versatility is, however, limited by their substrate scope, and new IREDs are needed. Current IREDs are closely related to the initially characterized enzymes, as their discovery has been driven by sequence homology searches. Here, we demonstrate a functional genomics approach based on biosynthetic promiscuity, guided by the identification of C=N reducing enzymes acting on large, complex substrates in biosynthetic pathways. These substrate-promiscuous biocatalysts share low homology to existing IREDs and fall into distinct functional enzyme families, yet they catalyze the hydrogenation of non-native imines as well as the reductive amination of simple ketones. Venturing further into sequence space without the constraints of close homology, but instead guided by functional promiscuity, has thus led us to distinct, previously unrecognized and unexplored areas of sequence space for mining IREDs for synthesis.
{"title":"Expanding the repertoire of imine reductases by mining divergent biosynthetic pathways for promiscuous reactivity","authors":"Godwin A. Aleku, Florian Hollfelder","doi":"10.1016/j.checat.2024.101160","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101160","url":null,"abstract":"Imine reductases (IREDs) are invaluable catalysts for enantioselective imine reduction and reductive amination of carbonyl compounds. Their synthetic versatility is, however, limited by their substrate scope, and new IREDs are needed. Current IREDs are closely related to the initially characterized enzymes, as their discovery has been driven by sequence homology searches. Here, we demonstrate a <em>functional</em> genomics approach based on biosynthetic promiscuity, guided by the identification of C=N reducing enzymes acting on large, complex substrates in biosynthetic pathways. These substrate-promiscuous biocatalysts share low homology to existing IREDs and fall into distinct functional enzyme families, yet they catalyze the hydrogenation of non-native imines as well as the reductive amination of simple ketones. Venturing further into sequence space without the constraints of close homology, but instead guided by functional promiscuity, has thus led us to distinct, previously unrecognized and unexplored areas of sequence space for mining IREDs for synthesis.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":"235 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fluorinated molecules are widely used in drug discovery and materials science. However, the efficient construction of a C(sp3)–F bond from diverse carboxylic acids with a promising low-cost photocatalyst to replace expensive metal catalysts remains a significant challenge. Herein, we present a cost-effective, metal-free, and highly efficient photocatalytic approach for the direct decarboxylative fluorination of aliphatic carboxylic acids and diacids via photoexcited aliphatic ketones. This reaction (milligram to gram scale) can be achieved in just a few minutes with low-power irradiation using a broad range of wavelengths, spanning from visible to ultraviolet light. Our investigation revealed that photoexcited ketones, commonly employed as hydrogen atom transfer (HAT) catalysts for various C(sp3)–H bond functionalizations, exhibit a distinct preference for single-electron transfer (SET) in the decarboxylation of aliphatic carboxylic acids when combined with Selectfluor and Na2HPO4.
{"title":"Ketones as ideal photocatalysts for decarboxylative fluorination and a competition with C(sp3)-H fluorination","authors":"Yu Zhang, Jiahui Qian, Miao Wang, Yahao Huang, Hansjörg Grützmacher, Peng Hu","doi":"10.1016/j.checat.2024.101162","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101162","url":null,"abstract":"Fluorinated molecules are widely used in drug discovery and materials science. However, the efficient construction of a C(sp<sup>3</sup>)–F bond from diverse carboxylic acids with a promising low-cost photocatalyst to replace expensive metal catalysts remains a significant challenge. Herein, we present a cost-effective, metal-free, and highly efficient photocatalytic approach for the direct decarboxylative fluorination of aliphatic carboxylic acids and diacids via photoexcited aliphatic ketones. This reaction (milligram to gram scale) can be achieved in just a few minutes with low-power irradiation using a broad range of wavelengths, spanning from visible to ultraviolet light. Our investigation revealed that photoexcited ketones, commonly employed as hydrogen atom transfer (HAT) catalysts for various C(sp<sup>3</sup>)–H bond functionalizations, exhibit a distinct preference for single-electron transfer (SET) in the decarboxylation of aliphatic carboxylic acids when combined with Selectfluor and Na<sub>2</sub>HPO<sub>4</sub>.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":"41 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-24DOI: 10.1016/j.checat.2024.101154
Luyao Wang, Yifan Gu, Fengting Li
Photoreduction of CO2 to a single gas product requires catalysts with remarkable product selectivity because CO and CH4 are usually produced simultaneously. We propose that the charge-density regulation within metal-organic frameworks (MOFs) could effectively manage the binding energy required for reduction intermediates, thereby controlling the ultimate product formation to obtain CO with 100% selectivity. Herein, two iso-structured Fe-based MOFs bearing linkers with different electronic properties were prepared and exhibited favorable CO2 photoreduction performance without any cocatalyst or photosensitizer. In particular, the linker was altered to reduce the transfer of charges from Fe to the surrounding ligands, regulating the charge-density distribution. The binding affinity with the key COH∗ was remarkably weakened and behaved thermodynamically unfavorably compared with CO desorption, resulting in 100% CO generation. These insights provide a catalyst design strategy for controlling reduction species and improving product selectivity, which could encourage the development of intriguing MOF material customization for photocatalysis.
将 CO2 光还原成单一气体产物需要催化剂具有显著的产物选择性，因为 CO 和 CH4 通常是同时产生的。我们提出，金属有机框架（MOFs）内的电荷密度调节可有效管理还原中间产物所需的结合能，从而控制最终产物的形成，以 100% 的选择性获得 CO。本文制备了两种具有不同电子特性连接体的等结构铁基 MOFs，它们在不使用任何共催化剂或光敏剂的情况下表现出良好的 CO2 光还原性能。特别是，连接体的改变减少了电荷从 Fe 向周围配体的转移，从而调节了电荷的密度分布。与关键 COH∗ 的结合亲和力明显减弱，与 CO 解吸相比，热力学行为不利，导致 100% CO 生成。这些见解为控制还原物种和提高产物选择性提供了催化剂设计策略，有助于开发用于光催化的定制化 MOF 材料。
{"title":"Photoreduction of CO2 to complete CO catalyzed by charge-density-regulating metal-organic frameworks","authors":"Luyao Wang, Yifan Gu, Fengting Li","doi":"10.1016/j.checat.2024.101154","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101154","url":null,"abstract":"Photoreduction of CO<sub>2</sub> to a single gas product requires catalysts with remarkable product selectivity because CO and CH<sub>4</sub> are usually produced simultaneously. We propose that the charge-density regulation within metal-organic frameworks (MOFs) could effectively manage the binding energy required for reduction intermediates, thereby controlling the ultimate product formation to obtain CO with 100% selectivity. Herein, two iso-structured Fe-based MOFs bearing linkers with different electronic properties were prepared and exhibited favorable CO<sub>2</sub> photoreduction performance without any cocatalyst or photosensitizer. In particular, the linker was altered to reduce the transfer of charges from Fe to the surrounding ligands, regulating the charge-density distribution. The binding affinity with the key COH∗ was remarkably weakened and behaved thermodynamically unfavorably compared with CO desorption, resulting in 100% CO generation. These insights provide a catalyst design strategy for controlling reduction species and improving product selectivity, which could encourage the development of intriguing MOF material customization for photocatalysis.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":"1 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142489082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.checat.2024.101156
Hong Zhang, Ping Liu
Capturing catalytic behaviors under operational conditions is pivotal to gaining a mechanistic understanding and promoting the design of robust catalysts. The challenge lies in the difficulty of monitoring real-time surface dynamics driven by catalyst-environment interactions. Here, we introduce a framework based on density functional calculations and kinetic modeling. This framework significantly improves the accuracy of theoretical models’ descriptions of experimental observations by quantifying environmental impacts on surface phases and active sites. CO2 hydrogenation over Pd-based catalysts is taken as a showcase. The observed selectivity variations of Pd and Pd-M bimetallic catalysts strongly correlate with hydrogen coverage maintained under typical CO2 hydrogenation conditions. By reducing the amount of surface hydrogen, the selectivity tuned effectively from formic acid toward CO and methanol. This study not only deepens the comprehension of dynamics of active sites under active chemical conditions but also introduces an alternative opportunity for catalytic tuning by modulating catalyst-environment interactions.
捕捉运行条件下的催化行为对于从机理上理解和促进稳健催化剂的设计至关重要。挑战在于难以监测催化剂与环境相互作用驱动的实时表面动态。在此，我们介绍一种基于密度泛函计算和动力学建模的框架。该框架通过量化环境对表面相和活性位点的影响，大大提高了理论模型描述实验观察结果的准确性。二氧化碳在钯基催化剂上的加氢反应就是一个例子。观察到的 Pd 和 Pd-M 双金属催化剂的选择性变化与典型 CO2 加氢条件下保持的氢覆盖率密切相关。通过减少表面氢的数量，选择性从甲酸有效地调整到 CO 和甲醇。这项研究不仅加深了人们对活性化学条件下活性位点动态的理解，还为通过调节催化剂与环境的相互作用进行催化调节提供了另一个机会。
{"title":"Fine-tuning catalytic selectivity by modulating catalyst-environment interactions: CO2 hydrogenation over Pd-based catalysts","authors":"Hong Zhang, Ping Liu","doi":"10.1016/j.checat.2024.101156","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101156","url":null,"abstract":"Capturing catalytic behaviors under operational conditions is pivotal to gaining a mechanistic understanding and promoting the design of robust catalysts. The challenge lies in the difficulty of monitoring real-time surface dynamics driven by catalyst-environment interactions. Here, we introduce a framework based on density functional calculations and kinetic modeling. This framework significantly improves the accuracy of theoretical models’ descriptions of experimental observations by quantifying environmental impacts on surface phases and active sites. CO<sub>2</sub> hydrogenation over Pd-based catalysts is taken as a showcase. The observed selectivity variations of Pd and Pd-M bimetallic catalysts strongly correlate with hydrogen coverage maintained under typical CO<sub>2</sub> hydrogenation conditions. By reducing the amount of surface hydrogen, the selectivity tuned effectively from formic acid toward CO and methanol. This study not only deepens the comprehension of dynamics of active sites under active chemical conditions but also introduces an alternative opportunity for catalytic tuning by modulating catalyst-environment interactions.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":"75 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.checat.2024.101158
Yimeng Cao, Jun Chen, Chunmei Ding, Ying Zhang, Haibo Chi, Yan Liu, Can Li
α-Amino acids (α-aa) play a significant role in pharmaceutical and chemical industries. Here, we reported an electrochemical tandem system that couples the anodic dehydrogenation of amines and the cathodic carboxylation of imines. Based on a designed Lewis acid (LA)-enriched CeO2 with indium (denoted as In-CeOx) as cathodic electrocatalysts, we achieved 82% and 92% yields of stable imines and α-aa in a membrane-separated cell system, respectively. In a membrane-free system, quaternary or cyclic α-aa could be directly obtained from amines and CO2 with up to 83% yield. Mechanistic investigations have elucidated that the incorporation of indium (In) yields elevated levels of LA sites. These enhanced LA sites play a pivotal role in facilitating the capture and activation of imines. This function of In-CeOx, coupled with CO2 activation mediated by In species, is proven to be crucial for achieving high reactivity and selectivity in the cathodic carboxylation reaction.
α-氨基酸（α-aa）在制药和化学工业中发挥着重要作用。在此，我们报告了一种将胺的阳极脱氢和亚胺的阴极羧化耦合在一起的电化学串联系统。基于设计的富含路易斯酸（LA）和铟（In-CeOx）的 CeO2 作为阴极电催化剂，我们在膜分离电池系统中分别获得了 82% 和 92% 的稳定亚胺和 α-aa 产率。在无膜系统中，可直接从胺和二氧化碳中获得四元或环状 α-aa，产率高达 83%。机理研究阐明，铟（In）的加入会产生更多的 LA 位点。这些增强的 LA 位点在促进亚胺的捕获和活化方面发挥了关键作用。事实证明，In-CeOx 的这一功能，加上 In 物种介导的二氧化碳活化，对于在阴极羧化反应中实现高反应性和选择性至关重要。
{"title":"Electrochemical CO2 fixation with amines to synthesize α-amino acids","authors":"Yimeng Cao, Jun Chen, Chunmei Ding, Ying Zhang, Haibo Chi, Yan Liu, Can Li","doi":"10.1016/j.checat.2024.101158","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101158","url":null,"abstract":"α-Amino acids (α-aa) play a significant role in pharmaceutical and chemical industries. Here, we reported an electrochemical tandem system that couples the anodic dehydrogenation of amines and the cathodic carboxylation of imines. Based on a designed Lewis acid (LA)-enriched CeO<sub>2</sub> with indium (denoted as In-CeO<sub>x</sub>) as cathodic electrocatalysts, we achieved 82% and 92% yields of stable imines and α-aa in a membrane-separated cell system, respectively. In a membrane-free system, quaternary or cyclic α-aa could be directly obtained from amines and CO<sub>2</sub> with up to 83% yield. Mechanistic investigations have elucidated that the incorporation of indium (In) yields elevated levels of LA sites. These enhanced LA sites play a pivotal role in facilitating the capture and activation of imines. This function of In-CeO<sub>x</sub>, coupled with CO<sub>2</sub> activation mediated by In species, is proven to be crucial for achieving high reactivity and selectivity in the cathodic carboxylation reaction.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":"1 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-22DOI: 10.1016/j.checat.2024.101131
Michael S. Crocker, Jung-Ying Lin, Reem Nsouli, Nathan D. McLaughlin, Djamaladdin G. Musaev, Aliyeh Mehranfar, Ernesto R. Lopez, Laura K.G. Ackerman-Biegasiewicz
Visible-light-promoted Fe photocatalysis is a sustainable strategy for synthetic chemistry. Yet, the adoption of Fe photocatalytic reactions proceeding through a ligand-to-metal charge transfer event has been limited to simple substrates in many transformations. An outstanding challenge in the field is the selection of tunable ligand scaffolds providing general reactivity. In this work, we describe the use of aliphatic amines as ligands in Fe-promoted decarboxylative Giese-type additions. Unlike prior photoredox reports, this method enables the coupling of substrates with free amines, alcohols, and a boronic ester. To gain insight into the role of diethylenetriamine (L1), ligated Fe salts were investigated using ultraviolet-visible spectroscopy, thermal gravimetric analysis, and density functional theory. These studies support the formation of a photoactive octahedral carboxylate (L1)Fe(OCOR)3. As an increasing number of photocatalytic reactions proceed using earth-abundant metals, the use of these ligands expands the possibility of applying Fe to a broad array of transformations.
{"title":"Transformative ligand effects in Fe-photocatalyzed Giese-type additions","authors":"Michael S. Crocker, Jung-Ying Lin, Reem Nsouli, Nathan D. McLaughlin, Djamaladdin G. Musaev, Aliyeh Mehranfar, Ernesto R. Lopez, Laura K.G. Ackerman-Biegasiewicz","doi":"10.1016/j.checat.2024.101131","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101131","url":null,"abstract":"Visible-light-promoted Fe photocatalysis is a sustainable strategy for synthetic chemistry. Yet, the adoption of Fe photocatalytic reactions proceeding through a ligand-to-metal charge transfer event has been limited to simple substrates in many transformations. An outstanding challenge in the field is the selection of tunable ligand scaffolds providing general reactivity. In this work, we describe the use of aliphatic amines as ligands in Fe-promoted decarboxylative Giese-type additions. Unlike prior photoredox reports, this method enables the coupling of substrates with free amines, alcohols, and a boronic ester. To gain insight into the role of diethylenetriamine (<strong>L1</strong>), ligated Fe salts were investigated using ultraviolet-visible spectroscopy, thermal gravimetric analysis, and density functional theory. These studies support the formation of a photoactive octahedral carboxylate (<strong>L1</strong>)Fe(OCOR)<sub>3</sub>. As an increasing number of photocatalytic reactions proceed using earth-abundant metals, the use of these ligands expands the possibility of applying Fe to a broad array of transformations.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":"85 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142486559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-21DOI: 10.1016/j.checat.2024.101147
Noah H. Watkins, Yungeun Kwon, Qiu Wang
We report a copper-catalyzed 1,4-selective aminooxygenation of 1,3-dienes as a direct entry to 1,4-allylic amino alcohols. The reactions are effective on a diverse range of amide-, urea-, and ester-containing 1,3-dienes, allowing for the facile installation of aliphatic alkylamines and free alcohol. The transformation was initiated by a copper-catalyzed electrophilic amination using O-benzoylhydroxylamines, and a carbonyl-assisted oxygen migration delivered the exclusive 1,4-selectivity in the subsequent oxygenation step. Inspired by these mechanistic insights, we also realized an unprecedented 1,4-aminothiolation of thioamide-containing 1,3-dienes by leveraging a novel thiol migration.
{"title":"Copper-catalyzed 1,4-aminohydroxylation and aminothiolation of 1,3-dienes by carbonyl-assisted migration","authors":"Noah H. Watkins, Yungeun Kwon, Qiu Wang","doi":"10.1016/j.checat.2024.101147","DOIUrl":"https://doi.org/10.1016/j.checat.2024.101147","url":null,"abstract":"We report a copper-catalyzed 1,4-selective aminooxygenation of 1,3-dienes as a direct entry to 1,4-allylic amino alcohols. The reactions are effective on a diverse range of amide-, urea-, and ester-containing 1,3-dienes, allowing for the facile installation of aliphatic alkylamines and free alcohol. The transformation was initiated by a copper-catalyzed electrophilic amination using <em>O</em>-benzoylhydroxylamines, and a carbonyl-assisted oxygen migration delivered the exclusive 1,4-selectivity in the subsequent oxygenation step. Inspired by these mechanistic insights, we also realized an unprecedented 1,4-aminothiolation of thioamide-containing 1,3-dienes by leveraging a novel thiol migration.","PeriodicalId":53121,"journal":{"name":"Chem Catalysis","volume":"111 1","pages":""},"PeriodicalIF":9.4,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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