bond arylation of benzyl ethers with Knochel-type arylzinc reagents has been developed. This transition-metal-catalyst-free reaction proceeds well under mild conditions in a simple and effective manner and enables the synthesis of a wide range of potentially biologically active benzyl ethers by using highly functionalized organozincreagents as a carbon nucleophile.
Comparison of the Reaction of Benzylammonium N-Methylides with That of Benzylsulfonium S-Methylides.
作者:Tomofumi NISHIMURA、Chen ZHANG、Yasuhiro MAEDA、Naohiro SHIRAI、Shin-ichi IKEDA、Yoshiro SATO
DOI:10.1248/cpb.47.267
日期:——
Allylbenzylsulfonium S-methylides 8S and dibenzylsulfonium S-methylides 18S have been generated by the fluoride ion-induced desilylation of S-benzyl-S-[(trimethylsilyl)methyl](alk-2-enyl)sulfonium salts 4S and S-benzyl-S-[(trimethylsilyl)methyl](4-substituted benzyl)sulfonium salts 7S, and the isomerized products are compared with those of the corresponding N-methylides. S-Methylides 8S selectively rearrange toward the allyl groups (path a in Chart 2), whereas rearrangement to the benzyl groups (path b) competitively occurs in N-methylides 8N. Isomerization of S-methylides 18S to S-benzylides 19S and 20S competes with sigmatropic rearrangement to the benzyl groups (paths a and b in Chart 3), whereas the isomerization of N-methylides 18N is not observed.