{"title":"Sterically Controlled Lewis Acid-Base Interaction Toward para-Selective Borylation of Aromatic Aldimines and Benzylamines.","authors":"Saikat Guria, Mirja Md Mahamudul Hassan, Sayan Dey, Krishna Nand Singh, Buddhadeb Chattopadhyay","doi":"10.1002/anie.202409010","DOIUrl":null,"url":null,"abstract":"<p><p>Site-selective C-H bond functionalization of arenes at the para position remains extremely challenging primarily due to its relative inaccessibility from the catalytic site. As a consequence, it is significantly restricted to limited molecular scaffolds. Herein, we report a method for the para-C-H borylation of aromatic aldimines and benzylamines using commercially available ligands under iridium catalysis. The established method displays excellent para selectivity for variously substituted aromatic aldimines, benzylamines and bioactive molecules. Based on several control experiments, it is proposed that a Lewis acid-base interaction between the nitrogen and boron functionality guides the para selectivity via a steric shield for the aromatic aldimines, where Bpin acts as a transient directing group. However, the steric shield of the in situ generated N-Bpin moiety controlled the overall selectivity for the para borylation of benzylamines.</p>","PeriodicalId":125,"journal":{"name":"Angewandte Chemie International Edition","volume":null,"pages":null},"PeriodicalIF":16.1000,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Angewandte Chemie International Edition","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1002/anie.202409010","RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2024/9/5 0:00:00","PubModel":"Epub","JCR":"Q1","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Site-selective C-H bond functionalization of arenes at the para position remains extremely challenging primarily due to its relative inaccessibility from the catalytic site. As a consequence, it is significantly restricted to limited molecular scaffolds. Herein, we report a method for the para-C-H borylation of aromatic aldimines and benzylamines using commercially available ligands under iridium catalysis. The established method displays excellent para selectivity for variously substituted aromatic aldimines, benzylamines and bioactive molecules. Based on several control experiments, it is proposed that a Lewis acid-base interaction between the nitrogen and boron functionality guides the para selectivity via a steric shield for the aromatic aldimines, where Bpin acts as a transient directing group. However, the steric shield of the in situ generated N-Bpin moiety controlled the overall selectivity for the para borylation of benzylamines.
期刊介绍:
Angewandte Chemie, a journal of the German Chemical Society (GDCh), maintains a leading position among scholarly journals in general chemistry with an impressive Impact Factor of 16.6 (2022 Journal Citation Reports, Clarivate, 2023). Published weekly in a reader-friendly format, it features new articles almost every day. Established in 1887, Angewandte Chemie is a prominent chemistry journal, offering a dynamic blend of Review-type articles, Highlights, Communications, and Research Articles on a weekly basis, making it unique in the field.