A flexible stereoselective and convergent cum divergent approach to the synthesis of two 13-membered macrolides through a common skeleton present in their structure is described in two different routes, with good overall yield. The key synthetic reactions utilized include Keck allylation, Evans asymmetric methylation, Grubbs metathesis and Julia-Kocienski olefination reaction.
{"title":"Total synthesis of marine-derived azole resistant antifungal agent (-)-melearoride A and antibiotic (-)-PF1163B","authors":"Srihari Pabbaraja, Bharath Yasam","doi":"10.1055/a-1942-6969","DOIUrl":"https://doi.org/10.1055/a-1942-6969","url":null,"abstract":"A flexible stereoselective and convergent cum divergent approach to the synthesis of two 13-membered macrolides through a common skeleton present in their structure is described in two different routes, with good overall yield. The key synthetic reactions utilized include Keck allylation, Evans asymmetric methylation, Grubbs metathesis and Julia-Kocienski olefination reaction.","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43659489","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}
A concise and diastereoselective total synthesis of tetraketide and euscapholide is described in ten steps in 10.6% overall yield from acetaldehyde and (S)-pent-4-ene-1,2-diol. Jacobsen hydrolytic kinetic resolution, Prins cyclization, ring-closing metathesis and oxa-Michael addition reactions are the key steps involved in the synthesis.
{"title":"Stereoselective Synthesis of Euscapholide and Tetraketide via Prins Cyclisation and Ring-Closing Metathesis","authors":"D. Biradar, Y. Mane, B. S. Subba Reddy","doi":"10.1055/s-0042-1751381","DOIUrl":"https://doi.org/10.1055/s-0042-1751381","url":null,"abstract":"A concise and diastereoselective total synthesis of tetraketide and euscapholide is described in ten steps in 10.6% overall yield from acetaldehyde and (S)-pent-4-ene-1,2-diol. Jacobsen hydrolytic kinetic resolution, Prins cyclization, ring-closing metathesis and oxa-Michael addition reactions are the key steps involved in the synthesis.","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":"06 1","pages":"312 - 318"},"PeriodicalIF":2.5,"publicationDate":"2022-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41517644","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}
Mohammad Saif Ali, Ramesh P.I, Subhash Ghosh, M. Tatina
We report the strategy for the stereoselective synthesis of 1,2-trans glycosides in the absence of NGP (neighboring group participation). Present protocol for the selective glycosylation mainly rely on catalyst control rather than protecting group selection. Using this protocol, several glycosides were prepared. Cost effective zinc acetate was found to be the best catalyst that provided desired 1,2-trans glycosides from glucose and mannose derived glycosyl halides at room temperature unlike traditional cryogenic conditions.
{"title":"Zinc acetate catalyzed stereoselective 1,2 trans glycosylation using glycosyl chlorides","authors":"Mohammad Saif Ali, Ramesh P.I, Subhash Ghosh, M. Tatina","doi":"10.1055/a-1941-3801","DOIUrl":"https://doi.org/10.1055/a-1941-3801","url":null,"abstract":"We report the strategy for the stereoselective synthesis of 1,2-trans glycosides in the absence of NGP (neighboring group participation). Present protocol for the selective glycosylation mainly rely on catalyst control rather than protecting group selection. Using this protocol, several glycosides were prepared. Cost effective zinc acetate was found to be the best catalyst that provided desired 1,2-trans glycosides from glucose and mannose derived glycosyl halides at room temperature unlike traditional cryogenic conditions.","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":"1 1","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41415840","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}
Paseka T. Moshapo, Blessing D. Mkhonazi, Euphrent M. Mabila
Amide functional groups are a structural feature in a vast array of beneficial organic molecules. This has resulted in a surge in new methodologies developed to enable access to this functional group using a broad range of coupling partners. Herein, we report a palladium-catalysed reductive aminocarbonylation of aryl bromides and iodides with nitroarenes to afford the respective amide products. The developed protocol employs Mo(CO)6 as a carbonyl source and a combination of Zn and TMSCl as co-reducing agents. For most substrates, the anticipated amide products were obtained in modest to high amide product yields.
{"title":"Palladium-Catalysed Reductive Aminocarbonylation of Aryl Bromides and Iodides with Nitroarenes","authors":"Paseka T. Moshapo, Blessing D. Mkhonazi, Euphrent M. Mabila","doi":"10.1055/s-0040-1720041","DOIUrl":"https://doi.org/10.1055/s-0040-1720041","url":null,"abstract":"Amide functional groups are a structural feature in a vast array of beneficial organic molecules. This has resulted in a surge in new methodologies developed to enable access to this functional group using a broad range of coupling partners. Herein, we report a palladium-catalysed reductive aminocarbonylation of aryl bromides and iodides with nitroarenes to afford the respective amide products. The developed protocol employs Mo(CO)6 as a carbonyl source and a combination of Zn and TMSCl as co-reducing agents. For most substrates, the anticipated amide products were obtained in modest to high amide product yields.","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46480411","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}
V. Batchu, H. Bharathkumar, J. S. Krishna, Banothu Surender
This review reports on the total synthesis of conduramines, which are formally derived from conduritols, these molecules are mainly contains trihydroxy aminocyclohexene core. Analysis of the different strategies developed to prepare these aminocyclohexene triols and their derivatives has been carried out with special attention paid to the methods employed for the insertion of chiral amine moiety.
{"title":"Approaches to the total synthesis of conduramines: A Review","authors":"V. Batchu, H. Bharathkumar, J. S. Krishna, Banothu Surender","doi":"10.1055/a-1933-0602","DOIUrl":"https://doi.org/10.1055/a-1933-0602","url":null,"abstract":"This review reports on the total synthesis of conduramines, which are formally derived from conduritols, these molecules are mainly contains trihydroxy aminocyclohexene core. Analysis of the different strategies developed to prepare these aminocyclohexene triols and their derivatives has been carried out with special attention paid to the methods employed for the insertion of chiral amine moiety.","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44724715","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}
C–H bond functionalization is one of the most effective strategies for the rapid synthesis of cyclic amines containing substituents in the ring, which are core structures of many bioactive molecules. It is, however, much more challenging to perform this strategy on remote C–H bonds compared to α-C–H bonds of cyclic amines. This graphical review aims to provide a concise overview on transition metal-catalyzed methods for the remote C–H bond functionalization of cyclic amines. Examples are categorized and demonstrated according to mechanistic pathways that initiate the reaction of cyclic amine substrates. Selected substrate scope and detailed reaction mechanisms are given when necessary.
{"title":"Transition Metal-Catalyzed Remote C–H Bond Functionalization of Cyclic Amines","authors":"Weijie Chen, Xiaoyu Yang, Xiaobei Cao","doi":"10.1055/a-1929-9789","DOIUrl":"https://doi.org/10.1055/a-1929-9789","url":null,"abstract":"C–H bond functionalization is one of the most effective strategies for the rapid synthesis of cyclic amines containing substituents in the ring, which are core structures of many bioactive molecules. It is, however, much more challenging to perform this strategy on remote C–H bonds compared to α-C–H bonds of cyclic amines. This graphical review aims to provide a concise overview on transition metal-catalyzed methods for the remote C–H bond functionalization of cyclic amines. Examples are categorized and demonstrated according to mechanistic pathways that initiate the reaction of cyclic amine substrates. Selected substrate scope and detailed reaction mechanisms are given when necessary.","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48153677","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}
N. Rastogi, L. Devi, Poornima Mishra, Ayush Pokhriyal
An efficient organo-photocatalytic method for the synthesis of tetrasubstituted pyrroles bearing a ketone, ester, alcohol, or nitro group at the 3-position has been developed. The reaction involves visible-light-mediated formal [3+2] dipolar cycloaddition between 2H-azirines and α-substituted nitroalkenes followed by a denitration or debromination sequence. The notable features of the protocol are excellent regioselectivity, wide substrate scope, and high yields of the products.
{"title":"Organo-photocatalytic Synthesis of Functionalized Pyrroles from 2H-Azirines and α-Substituted Nitroalkenes","authors":"N. Rastogi, L. Devi, Poornima Mishra, Ayush Pokhriyal","doi":"10.1055/s-0042-1751360","DOIUrl":"https://doi.org/10.1055/s-0042-1751360","url":null,"abstract":"An efficient organo-photocatalytic method for the synthesis of tetrasubstituted pyrroles bearing a ketone, ester, alcohol, or nitro group at the 3-position has been developed. The reaction involves visible-light-mediated formal [3+2] dipolar cycloaddition between 2H-azirines and α-substituted nitroalkenes followed by a denitration or debromination sequence. The notable features of the protocol are excellent regioselectivity, wide substrate scope, and high yields of the products.","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44193674","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}
Natural or artificial enzymes are used in biocatalytic processes to produce high-value fine chemicals, most notably chiral pharmaceutical intermediates. On the other hand, there are few instances of the enzymatic production of bulk compounds.1 In particular production of polymer precursors such as -caprolactone, currently obtained from cyclohexanone utilizing peracetic acid; where Baeyer–Villiger monooxygenases (BVMOs) are potential alternative catalysts to carry out the reaction under much milder conditions.2 Bulk manufacturing of feedstock chemicals utilizing biocatalysts such as BVMO has yet to be accomplished due to a number of reasons.3 The versatility of BVMOs is highlighted in this Spotlight, along with various instances of how protein engineering has been employed to circumvent some of the disadvantages of BVMO use. BVMOs are flavin-reliant enzymes that utilize molecular oxygen and NAD(P)H to catalyze a number of oxidation processes, including Baeyer–Villiger oxidations (Table 1).4,5 The genes to encode them were discovered at the beginning of this century.6 Even though the biochemical reason for the retention of these residues was unclear until recently, the sequence pattern has shown to be quite useful for mining genomes for new BVMOs.7 Although the genomes of higher animals and plants do not include any type I BVMOs, bacteria are rich in BVMOs, with one BVMO per genome on average.8 These enzymes are notably common among the Actinomycetes, making them an intriguing source of new BVMOs.9 Fungal genomes are also rather rich in BVMOs but have not yet been fully investigated.10 The crucial functions that BVMOs play in microbial metabolic pathways have recently been confirmed by investigations on the biotransformation of natural compounds.11–13
{"title":"Baeyer–Villiger Monooxygenases (BVMOs) as Biocatalysts","authors":"P. Chawla, Chandrakant Sahu","doi":"10.1055/s-0042-1751359","DOIUrl":"https://doi.org/10.1055/s-0042-1751359","url":null,"abstract":"Natural or artificial enzymes are used in biocatalytic processes to produce high-value fine chemicals, most notably chiral pharmaceutical intermediates. On the other hand, there are few instances of the enzymatic production of bulk compounds.1 In particular production of polymer precursors such as -caprolactone, currently obtained from cyclohexanone utilizing peracetic acid; where Baeyer–Villiger monooxygenases (BVMOs) are potential alternative catalysts to carry out the reaction under much milder conditions.2 Bulk manufacturing of feedstock chemicals utilizing biocatalysts such as BVMO has yet to be accomplished due to a number of reasons.3 The versatility of BVMOs is highlighted in this Spotlight, along with various instances of how protein engineering has been employed to circumvent some of the disadvantages of BVMO use. BVMOs are flavin-reliant enzymes that utilize molecular oxygen and NAD(P)H to catalyze a number of oxidation processes, including Baeyer–Villiger oxidations (Table 1).4,5 The genes to encode them were discovered at the beginning of this century.6 Even though the biochemical reason for the retention of these residues was unclear until recently, the sequence pattern has shown to be quite useful for mining genomes for new BVMOs.7 Although the genomes of higher animals and plants do not include any type I BVMOs, bacteria are rich in BVMOs, with one BVMO per genome on average.8 These enzymes are notably common among the Actinomycetes, making them an intriguing source of new BVMOs.9 Fungal genomes are also rather rich in BVMOs but have not yet been fully investigated.10 The crucial functions that BVMOs play in microbial metabolic pathways have recently been confirmed by investigations on the biotransformation of natural compounds.11–13","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48729155","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}
Thaís do Nascimento Pinheiro, E. Barbosa, A. K. Jordão
The reagent sodium tungstate dihydrate has some special features which are very important in synthesis. For instance, it is a mild and efficient reagent used in oxidation. Based on reports from recent literature we are proposing this spotlight.
{"title":"Sodium Tungstate Dihydrate (Na2WO4.2H2O): A Mild Oxidizing and Efficient Reagent in Organic Synthesis","authors":"Thaís do Nascimento Pinheiro, E. Barbosa, A. K. Jordão","doi":"10.1055/a-1924-8008","DOIUrl":"https://doi.org/10.1055/a-1924-8008","url":null,"abstract":"The reagent sodium tungstate dihydrate has some special features which are very important in synthesis. For instance, it is a mild and efficient reagent used in oxidation. Based on reports from recent literature we are proposing this spotlight.","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49199409","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}
D. Ravi Kishore, Sreenivasulu Chinnabattigalla, Anil Balajirao Dapkekar, G. Satyanarayana
Coupling reactions stand amid the most significant reactions in synthetic organic chemistry. Of late, these coupling strategies are being viewed as a versatile synthetic tool for a wide range of organic transformations in many sectors of chemistry, ranging from indispensable synthetic scaffolds and natural products of biological significance to novel organic materials. Further, the usage of dual-catalysis in accomplishing various interesting cross-coupling transformations is an emerging field in synthetic organic chemistry, owing to their high catalytic performance rather than the usage of a single catalyst. In recent years, synthetic organic chemists have given considerable attention to hetero-dual catalysis, wherein these catalytic systems have been employed for the construction of versatile carbon-carbon [C(sp3)–C(sp3), C(sp3)–C(sp2), C(sp2)–C(sp2), etc.] and carbon-heteroatom (C-N, C-O, C-P, C-S, etc.) bonds. Therefore, in this mini-review, we are emphasizing recently developed various cross-coupling reactions catalysed by transition-metal dual-catalysis (i.e., using palladium and copper catalysts, and by omitting the reports on photoredox/metal catalysis).
偶联反应是合成有机化学中最重要的反应之一。最近，这些偶联策略被视为一种通用的合成工具，用于化学许多领域的广泛有机转化，从不可或缺的合成支架和具有生物学意义的天然产物到新型有机材料。此外，使用双催化剂来完成各种有趣的交叉偶联转化是合成有机化学中的一个新兴领域，因为它们具有较高的催化性能，而不是单一催化剂的使用。近年来，合成有机化学家非常关注杂双催化，这些催化体系被用于构建多用途的碳-碳[C(sp3) -C (sp3)， C(sp3) -C (sp2)， C(sp2) -C (sp2)等]和碳杂原子(C- n, C- o, C- p, C- s等)键。因此，在这篇综述中，我们重点介绍了最近发展的各种过渡金属双催化(即使用钯和铜催化剂，省略了光氧化还原/金属催化的报道)催化的交叉偶联反应。
{"title":"Recent Applications on Dual-Catalysis for C-C and C-X Cross-Coupling Reactions","authors":"D. Ravi Kishore, Sreenivasulu Chinnabattigalla, Anil Balajirao Dapkekar, G. Satyanarayana","doi":"10.1055/a-1896-4168","DOIUrl":"https://doi.org/10.1055/a-1896-4168","url":null,"abstract":"Coupling reactions stand amid the most significant reactions in synthetic organic chemistry. Of late, these coupling strategies are being viewed as a versatile synthetic tool for a wide range of organic transformations in many sectors of chemistry, ranging from indispensable synthetic scaffolds and natural products of biological significance to novel organic materials. Further, the usage of dual-catalysis in accomplishing various interesting cross-coupling transformations is an emerging field in synthetic organic chemistry, owing to their high catalytic performance rather than the usage of a single catalyst. In recent years, synthetic organic chemists have given considerable attention to hetero-dual catalysis, wherein these catalytic systems have been employed for the construction of versatile carbon-carbon [C(sp3)–C(sp3), C(sp3)–C(sp2), C(sp2)–C(sp2), etc.] and carbon-heteroatom (C-N, C-O, C-P, C-S, etc.) bonds. Therefore, in this mini-review, we are emphasizing recently developed various cross-coupling reactions catalysed by transition-metal dual-catalysis (i.e., using palladium and copper catalysts, and by omitting the reports on photoredox/metal catalysis).","PeriodicalId":22135,"journal":{"name":"SynOpen","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2022-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48818482","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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