The chiralBrønstedacid (1b or 1c) has been shown to initiate the Hosomi−Sakurai reaction of imines with excellent enantioselectivities. The combined Brønstedacid system has been developed to offer a new class of chiralBrønstedacidcatalysis. The present system proceeds through regeneration of the chiralBrønstedacid by proton transfer from additional Brønstedacid to silylated chiral Brønsted
Asymmetric Allylboration of Acyl Imines Catalyzed by Chiral Diols
作者:Sha Lou、Philip N. Moquist、Scott E. Schaus
DOI:10.1021/ja075204v
日期:2007.12.1
is directly applied to the synthesis of Maraviroc, the selective CCR5 antagonist with potent activity against HIV-1 infection. Mechanistic investigations of the allylboration reaction including IR, NMR, and mass spectrometry studies indicate that acyclic boronates are activated by chiral diols via exchange of one of the boronate alkoxy groups with activation of the acyl imine via hydrogen bonding.