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.
通过氟离子诱导 S-苄基-S-[(三甲基硅基)甲基](烷-2-烯基)锍盐 4S 和 S-苄基-S-[(三甲基硅基)甲基](4-取代苄基)锍盐 7S 的脱硅作用,生成了烯丙基锍 S-甲基化物 8S 和二苄基锍 S-甲基化物 18S、并将异构化产物与相应的 N-甲基化物的异构化产物进行比较。S 型甲基化物 8S 选择性地向烯丙基发生重排(图 2 中的路径 a),而 N 型甲基化物 8N 则竞争性地向苄基发生重排(路径 b)。S 型甲基化物 18S 异构化为 S 型苄基化物 19S 和 20S 时,会竞争性地向苄基发生重排(图 3 中的路径 a 和 b),而 N 型甲基化物 18N 则不会发生异构化。