Intramolecular Conjugate Addition of Alkenyl and Aryl Functions to Enones Initiated by Lithium−Iodine Exchange
摘要:
[GRAPHICS]Treatment of each of the substrates 20-26, 29, and 46-48 with t-BuLi in THF, in the presence of HMPA and TMSCl, provides good-to-excel lent yields of the intramolecular conjugate addition products 30-36, 37, and 49-51, respectively.
3-halo-2-propene-1-ols 13 by utilizing combinations of the Sonogashira coupling, allylation, and the Dess−Martin oxidation. The RCEM/dehydration for the synthesis of 1,3,5-tris(1-phenylethenyl)benzene derivative 4r and the RCEM/RCM/dehydration for the synthesis of 1,1′-binaphthyl derivative 19a are also presented as applications of this method.
Tandem ring‐closing enyne metathesis (RCEM)/ring‐closing olefin metathesis (RCM) of tetraenynes with Grubbs second‐generation catalyst, followed by elimination, was found to be a new and efficient synthetic approach to biaryl compounds. A preliminary asymmetric version of this approach, which used homochiral Ru–alkylidene catalysts, is also presented.