Carbohydrates as chiral auxiliaries: synthesis of 2-hydroxy-β-D-glucopyranosides
摘要:
A new 2-step, 1-pot procedure for the stereoselective glycosylation of allylic alcohols with 1,2-di-O-benzoyl-beta-D-glucopyranosides to produce 2-hydroxy-beta-D-glucopyranosides has been developed. The required precursor for the glycosylation was readily obtained from tri-O-benzyl-D-glucal in 2 steps (91% overall).
The catalytic Friedel–Crafts alkylation reaction of aromatic compounds with benzyl or allyl silyl ethers using Cl2Si(OTf)2 or Hf(OTf)4
作者:Isamu Shiina、Masahiko Suzuki
DOI:10.1016/s0040-4039(02)01376-x
日期:2002.9
The Friedel-Crafts alkylation reaction of various aromatic compounds with benzyl or allyl silyl ethers is effectively promoted under mild reaction conditions using Lewis acid catalysts. A mixture of the desired phenyltolylmethanes is obtained in 80% yield from toluene with benzyl dimethylsilyl or trimethylsilyl ether at 50degreesC in the presence of a catalytic amount of Cl2Si(OTf)(2) or Hf(OTf)(2). (C) 2002 Elsevier Science Ltd. All rights reserved.