Iridium-Catalyzed Aerobic α,β-Dehydrogenation of γ,δ-Unsaturated Amides and Acids: Activation of Both α- and β-C–H bonds through an Allyl–Iridium Intermediate
作者:Zhen Wang、Zhiqi He、Linrui Zhang、Yong Huang
DOI:10.1021/jacs.7b11351
日期:2018.1.17
Direct aerobic α,β-dehydrogenation of γ,δ-unsaturated amides and acids using a simple iridium/copper relay catalysis system is described. We developed a new strategy that overcomes the challenging issue associated with the low α-acidity of amides and acids. Instead of α-C-H metalation, this reaction proceeds by β-C-H activation, which results in enhanced α-acidity. Conjugated dienamides and dienoic acids
by the regio- and stereoselective ring opening of β, γ, and δ-lactones with unsaturated substituents at the ω-position using organocopperreagents such as halomagnesium diorganocuprates or Grignard reagents in the presence of copper(I) iodide. Both the organocopperreagents with primary, secondary, tertiary alkyl, and phenyl groups gave the corresponding carbon homologated alkenoic acids in good yields