B(C₆F₅)₃-catalyzed β-C(sp³)–H alkylation of tertiary amines with 2-aryl-3H-indol-3-ones

Abstract

The β-C-H functionalization of amines is one of the most powerful tools for the synthesis of saturated nitrogen-containing heterocycles in organic synthesis. However, the β-C–H functionalization of amines via redox-neutral...

Recent Advances in Catalysis Using Organoborane-Mediated Hydride Abstraction

“…In 2023, He, Zhao and co-workers reported the B(C6F5)3catalyzed β-alkylation of tertiary amines 82 with 3H-indol-3ones 83 to yield 2-alkylindolin-3-ones 84 (Scheme 10). 26 Scheme 10 Borane-mediated hydride abstraction facilitates the βfunctionalization of amines with 3H-indol-3-ones.…”

Accessing Highly Substituted Indoles via B(C6F5)3-Catalyzed Secondary Alkyl Group Transfer

“…Despite these advances, it remains necessary to develop new synthetic approaches that avoid the use of catalysts based on precious metals and diversify the range of accessible indole-containing molecules. Building upon our ongoing interest in the applications of boranes in catalysis, , we recently discovered that B­(C 6 F 5 ) 3 could be employed as a catalyst for the direct C(3)-alkylation of indoles and oxindoles using amines as alkyl donors, whereby the mechanism of alkyl transfer is initiated by B­(C 6 F 5 ) 3 -mediated α- N C­(sp 3 )–H hydride abstraction to form electrophilic iminium ions. − However, the method was restricted to the transfer of 1° alkyl groups, and almost exclusively to C(3)-methylation, in order to mitigate against anticipated unproductive pathways resulting from enamine formation when amine alkyl donors that contain β- N C­(sp 3 )–H bonds were employed. Despite the aforementioned challenge, herein, we describe a significant advance of this approach to include the B­(C 6 F 5 ) 3 -catalyzed transfer of 2° alkyl groups for the first time, enabling access to a more diverse range of valuable highly substituted indoles ( vide infra ).…”

Dihydropyrrole-3-thiones: one-pot synthesis from propargylamines, acyl chlorides and sodium sulfide

“…2–14 At the same time, the syntheses of pyrroles with a CS fragment at position 3 have been described just sporadically. 17 In addition, obtaining pyrrole-3-ones (pyrrole-3-thione precursors) is also a separate complex synthetic task due to the fact that the main methods for their synthesis are laborious and involve multiple steps. 18 With regard to dihydropyrrole-3-thiones, this class of pyrrole compounds has remained essentially unknown until this work.…”