Efficient alkylsulfanyl (SMe, SEt and SCH2Ph) and sulfanyl (SH) migration in the stereospecific synthesis of substituted tetrahydrofurans
摘要:
Treatment of a series of 4-RS-1,3-diols (R=Me, Et, Bn and H) with TsOH in CH2Cl2 gives substituted tetrahydrofurans. We discuss the scope of this reaction using structural variation of the migrating (RS) substitutent All reactions proceeed in high yield and give synthetically useful products. Copyright (C) 1996 Elsevier Science Ltd
Do the Electronic Effects of Sulfur Indeed Control the π-Selectivity of γ-Sulfenyl Enones? An Investigation
摘要:
The electronic effects of sulfur in gamma-sulfenyl enones are not transmitted to the carbonyl carbon through the pi bond as reported previously. The diastereoselectivity is rather controlled by a combination of several other factors. The steric effects arising from the substituents on the sulfur atom and the gamma-carbon and the bulk of the nucleophile constitute the major control elements.
RhH(PPh3)4, 1,2-bis(diphenylphosphino)ethane (dppe), and dimethyl disulfide, ketones without α-activating groups were α-methylthiolated with 1,2-diphenyl-2-methylthio-1-ethanone giving α-methylthio ketones. The reaction of unsymmetrical ketones proceeded at the more substituted carbons. The initial formation of kinetic α-methylthiolated products followed by their rearrangement to thermodynamic products was
Scope and limitations of the [1,2]-alkylsulfanyl (SMe, SEt and SCH2Ph) and sulfanyl (SH) migration in the stereospecific synthesis of substituted tetrahydrofurans †
作者:Jason Eames、Nikolai Kuhnert、Stuart Warren
DOI:10.1039/b007284m
日期:——
dichloromethane gives stereospecifically substituted tetrahydrofurans via a [1,2]-SR shift in near quantitative yield. We comment on the structural variation of the migrating (RS) substituent and that of the migration origin and terminus on the outcome of the title reaction. We also report on the surprising similarity between an alkylsulfanyl (RS) and sulfanyl (SH) migrating group.