Effect of chalcogenyl substituent on the course of allyl rearrangement at chalcogenation of 1,3-dichloropropene
作者:E. P. Levanova、V. S. Nikonova、V. A. Grabel’nykh、N. V. Russavskaya、A. I. Albanov、I. B. Rozentsveig、N. A. Korchevin
DOI:10.1134/s1070428016050018
日期:2016.5
dichalcogenides in a redox system hydrazine hydrate–KOH is governed by the possibility of an allyl rearrangement. In the presence of bases this rearrangement proceeds via carbanion partially stabilized by the chalcogenyl substituent. The effectivity of the stabilization and consequently the probability of the rearrangement varies in the series of substituents PhS > BnS > PhSe. In the stage of the direct nucleophilic
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.