Enantioselective Conjugate Addition of Boronic Acids to α,β-Unsaturated 2-Acyl Imidazoles Catalyzed by Chiral Diols
作者:Guo-Li Chai、Ping Zhang、En-Ze Yao、Junbiao Chang
DOI:10.1021/acs.joc.2c00929
日期:2022.7.15
Herein, we report the enantioselective conjugate addition of organic boronicacids to α,β-unsaturated 2-acyl imidazoles using (R)-3,3′-I2-BINOL as the catalyst. The catalytic system shows high efficiency and tolerance to alkenylboronic acids and heteroarylboronic acids. The corresponding Michael addition products were obtained in moderate to excellent yields and with moderate to excellent enantioselectivities
rearrangement, giving the γ,δ‐unsaturated acid, which underwent a substrate‐induced stereoselective bromolactonization to afford the expected all‐equatorial substituted bromo‐δ‐lactone. An unusual chemo‐selective aminolysis of the lactone resulted in the formation of a γ,δ‐epoxy‐amide in stereospecific manner. Base‐promoted cyclization of this intermediate and the subsequent Davis oxidation furnished the synthesis