Enantioselective Carbonyl Reverse Prenylation from the Alcohol or Aldehyde Oxidation Level Employing 1,1-Dimethylallene as the Prenyl Donor

摘要

In the course of studies aimed at the development of C-C bond-forming hydrogenations, highly enantioselective carbonyl allylation~(3d,e) and crotylation~(3f) employing allyl acetate and α-methyl allyl acetate as allyl and crotyl donors, respectively, were achieved under the conditions of iridium-catalyzed transfer hydrogenation. For such reductive couplings, 2-propanol was exploited as the hydrogen donor. Remarkably, primary alcohols may serve dually as hydrogen donors and aldehyde precursors, enabling carbonyl allylation or crotylation directly from the alcohol oxidation level.