Synergistic Lewis base and anion-binding catalysis for the enantioselective vinylogous addition of deconjugated butenolides to allenoates
作者:Vikas Kumar、Santanu Mukherjee
DOI:10.1039/c3cc46858e
日期:——
An enantioselective vinylogous umpolung addition of deconjugated butenolides to allenoates has been developed for the first time with the help of synergistic combination of an achiral phosphine and a chiral squaramide, and represents the first example of a catalytic enantioselective Cγ–Cγ bond formation between two different carbonyl partners.
reaction of substituted phenylketenes with diethylamine in acetonitrile were suggested to be the amideenols rather than the zwitterions on the basis of the theoretical calculations. A single broad band at 1674 cm−1 observed for reaction with the primary amines was attributed to overlap of two bands of the intermediate (amideenol) and the final product (amide). The substituenteffect for the second‐order
The asymmetric stretching frequencies of the ketene group of the m,p-substituted phenylketenes were found to be correlated with σ. The substituent effects for the second-order rate constants of phe...