Maia da Silva Santos B, Dos Santos Dupim M, Paula de Souza C, Messias Cardozo T, Gadini Finelli F. DABCO-promoted photocatalytic C-H functionalization of aldehydes.
Beilstein J Org Chem 2022;
17:2959-2967. [PMID:
35003372 PMCID:
PMC8712972 DOI:
10.3762/bjoc.17.205]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 12/07/2021] [Indexed: 11/29/2022] Open
Abstract
Herein we present a direct application of DABCO, an inexpensive and broadly accessible organic base, as a hydrogen atom transfer (HAT) abstractor in a photocatalytic strategy for aldehyde C–H activation. The acyl radicals generated in this step were arylated with aryl bromides through a well stablished nickel cross-coupling methodology, leading to a variety of interesting aryl ketones in good yields. We also performed computational calculations to shine light in the HAT step energetics and determined an optimized geometry for the transition state, showing that the hydrogen atom transfer between aldehydes and DABCO is a mildly endergonic, yet sufficiently fast step. The same calculations were performed with quinuclidine, for comparison of both catalysts and the differences are discussed.
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