Singlet Oxygen Promoted Carbon−Heteroatom Bond Cleavage in Dibenzyl Sulfides and Tertiary Dibenzylamines. Structural Effects and the Role of Exciplexes
作者:Enrico Baciocchi、Tiziana Del Giacco、Osvaldo Lanzalunga、Andrea Lapi
DOI:10.1021/jo701641b
日期:2007.12.1
obtained whereas sulfoxide formation became negligible when the reactions were carried out in the presence of a base. Through a careful product study for the oxidation of dibenzyl sulfide, in the presence and in the absence of Ph2SO, it was established that sulfone and cleavage product (benzaldehyde) do not come by the same route (involving the persulfoxide and the hydroperoxysulfonium ylide) as required
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.
direct synthesis of sulfides and sulfoxides under green conditions without using any metal catalyst is reported. For this purpose, we used benzyl bromides as starting materials in the presence of potassium thioacetate (PTA) and Oxone® which are low-cost, and readily accessible chemicals. This method is highly compatible with a variety of functional groups and delivered a series of sulfides, bis-sulfides