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
9-Azabicyclo[4.2.1]nonane skeleton was formed in one step by Lewis acid promoted reaction between 1-methoxycarbony1-2,5-dimethoxypyrrolidine and 1-ethoxy-1-trimethylsiloxy-1,4-pentadiene, and it was converted to (±)-anatoxin a.
1-甲氧基羰基1-2,5-二甲氧基吡咯烷与1-乙氧基-1-三甲基甲硅烷氧基-1,4-戊二烯通过路易斯酸促进反应一步形成9-氮杂双环[4.2.1]壬烷骨架,并转化为(±)-anatoxin a.