Kinetic and Thermodynamic Control in the Synthesis of Tetrahydro-Pyrans and -Furans from 1,4-Diols by Stereospecific Phenylsulfanyl (PhS) Migration: Competition Between <i>exo</i> and <i>endo</i> Transition States and between [1,2] and [1,4]Sulfanyl Participation
作者:Jason Eames、Nikolai Kuhnert、Francis H. Sansbury、Stuart Warren
DOI:10.1055/s-1999-2814
日期:1999.8
The factors controlling the cyclisation of 1,4-diols with PhS migration to give THPs rather than THFs are reassessed. Furthermore we provide evidence for a competition between [1,2] and [1,4] sulfanyl participation and cyclisation onto a five membered cyclic sulfonium salt.
Secondary and tertiary alcohols as nucleophiles in the stereospecific synthesis of substituted tetrahydrofurans by cyclisation of 1,3-diols with phenylsulfanyl migration
作者:Jason Eames、Maria A. de las Heras、Stuart Warren
DOI:10.1016/0040-4039(96)00737-x
日期:1996.6
Rearrangement of a series of 4-phenylsulfanyl-1,3-diols with TsOH gives tetrahydrofurans stereospecifically and in high yield even if the nucleophile is a secondary or tertiary alcohol. We discuss the stereochemistry and acceptable substution patterns of the diols which will carry out this reaction and define their limits. (C) 1996 Elsevier Science Ltd.
Stereochemically controlled synthesis of 1,8-dioxaspiro[4.5]decanes and 1-oxa-8-thiaspiro[4.5]decanes by phenylsulfanyl migration
作者:Jason Eames、David J. Fox、Maria A. de las Heras、Stuart Warren
DOI:10.1039/b001893g
日期:——
Single enantiomers and diastereoisomers of 2- and 3-alkyl-3-phenylsulfanyl-1,8-dioxa- and 1-oxa-8-thiaspiro[4.5]decanes can be prepared in good yield by acid-catalysed phenylsulfanyl (PhS-) migration. Either the syn- or anti-stereochemistry can be controlled by aldol reactions or by reduction of hydroxy-ketones.