Michael reactions of silylated nucleophiles with conjugated enones accompanied by silyl group transfer catalysed by copper(I) chloride under photoirradiation
作者:Michiharu Mitani、Yosinari Osakabe
DOI:10.1039/c39940001759
日期:——
Photoreaction of conjugated enones with silylated nucleophiles such as silyl acetals, silyl enol ethers and even an allyl silane resulted in the formation of Michael adducts accompanied by transfer of the silyl group.
Role reversal: The title reaction has been developed to deliver α‐amino acids under very mild reaction conditions (see scheme; dpppen=1,5‐bis(diphenylphosphino)pentane). The catalysis provides a new CN bond‐forming approach for the synthesis of α‐amino acids by using an umpolung, electrophilic amination strategy.
acetylenedicarboxylate is reacted with ketene alkyl trimethylsilyl acetals in the presence of a catalytic amount of zirconiumtetrachloride, dimethyl 2-alkoxycarbonyl-3-alkylidenebutanedioates are afforded. Although the silyl enol ether from acetophenone undergoes the same type of reaction, other trisubstituted silyl enol ethers such as those from butyrophenone and 3-pentanone fail to react with dimethyl