Asymmetric Michael additions of Grignard reagents to cinnamamides deriving from N-alkyl (R)-(−)-2-aminobutan-1-ol
作者:Joe¨l Touet、Sylvie Baudouin、Eric Brown
DOI:10.1016/s0957-4166(00)82287-9
日期:1992.5
Reaction of cinnamoyl chloride with various N-alkyl derivatives of (R)-(−)-2-aminobutan-1-ol (a readily available reagent) afforded the corresponding cinnamamides. Michael additions of Grignardreagents to the latter, followed by acidic hydrolysis, yielded optically active β-phenylalkanoic acids whose ee most generally were in the range 72–100%.
Herein, we report a sustainable approach for N-formylation of aromatic as well as aliphaticamines using sodium borohydride and carbon dioxide gas. The developed approach is catalyst free, and does not need pressure or a specialized reaction assembly. The reductive formylation of CO2 with sodium borohydride generates formoxy borohydride species in situ, as confirmed by 1H and 11B NMR spectroscopy.