Lewis acid induced rearrangement of 2,3-epoxy sulfides; regiospecific trapping of thiiranium ion intermediates with nitrogen heterocycles and amides. Use of imines as nucleophilic equivalents for the selective monoalkylation of primary amines
作者:Duncan M Gill、Neil A Pegg、Christopher M Rayner
DOI:10.1016/0040-4020(96)00036-1
日期:1996.3
The Lewisacidinduced conversion of 2,3-epoxysulfides into the corresponding 3-trimethylsilyloxy-1,2-thiiranium ions is described. Such intermediates react with silylated nitrogenheterocycles and amidesregiospecifically to form 1-substituted-3-hydroxy-2-thioethers in good to moderate yields with full stereochemical control. Exclusive N-alkylation is observed. When simple primaryamines are used
Reaction of α-amino esters and α-amino ester imines with thiiranium ion intermediates. Application to the synthesis of new potential aminopeptidase inhibitors and mechanistic implications
作者:Duncan M Gill、Neil A Pegg、Christopher M Rayner
DOI:10.1016/s0040-4020(97)00060-4
日期:1997.3
situ from 2,3-epoxy sulfides, to give an iminium ion which can be readily hydrolysed by aqueous base to liberate a secondary amine, the product of selective monoalkylation of the primary amino group. Overall yields for this process are only moderate, but can be improved by use of α-amino esters themselves as nucleophiles at low temperature. Interesting reactivity profiles of the thiiranium ion intermediates
Stereoselective synthesis of 2,3-epoxy sulphoxides.
作者:Christopher M. Rayner、Man S. Sin、Andrew D. Westwell
DOI:10.1016/s0040-4039(00)60882-1
日期:1992.11
Methods for the diastereoselective preparation of various 2,3-epoxy sulphoxides are described using a double enantioselective oxidation approach. Direct comparisons of the selectivity and efficiency of the Davis and Kagan asymmetric sulphur oxidation procedure are given.
Optically active 2,3-epoxy sulfides as precursors to 3-hydroxy-1,2-dithioethers and 3-hydroxy-1-alkenylthioethers
作者:Ian Forristal、Kevin R. Lawson、Christopher M. Rayner
DOI:10.1016/s0040-4039(99)01427-6
日期:1999.9
Procedures are reported far the conversion of 2,3-epoxysulfides to 3-hydroxy-1,2-dithioethers. Conventional nucleophilic ring opening using a thiolate gives a mixture of products resulting from ring opening at C-2 and C-3, with the latter predominating. With sodium thiolates in DMF a competing beta-elimination process is observed to form 3-hydroxy-1-alkenylthioethers. Alternatively, Lewis acid induced thiiranium ion generation from a 2,3-epoxy sulfide, and nucleophilic ring opening with S-trimethylsilylthiophenol gives 3-hydroxy-1,2-dithioethers with full regio- and stereo-control. (C) 1999 Elsevier Science Ltd. All rights reserved.
Homochiral 2,3-epoxy sulfides—powerful new synthetic building blocks providing stereoselective access to 2,3-epoxy sulfoxides, 2,3-dihydroxy sulfoxides and (E)-γ-hydroxy-α,β-unsaturated sulfoxides and sulfones. X-Ray molecular structure of rac-(2R*,3R*)-1-[(S*)-phenylsulfinyl] hexane-2,3-diol
作者:Andrew D. Westwell、Mark Thornton-Pett、Christopher M. Rayner
DOI:10.1039/p19950000847
日期:——
The stereoselective transformation of homochiral 2,3-epoxy sulfoxides into 2,3-epoxy sulfoxides is described. These intermediates undergo elimination under basic reaction conditions to give (E)-gamma-hydroxy-alpha,beta-unsaturated sulfoxides, and under Lewis acidic conditions form novel cyclic sulfoxonium salts which on hydrolysis give 2,3-dihydroxy sulfoxides with excellent stereochemical control. 2,3-Dihydroxy sulfoxides can also be converted into (E)-gamma-hydroxy-alpha,beta-unsaturated sulfoxides by elimination via a cyclic sulfite. The synthesis of (E)-gamma-hydroxy-alpha,beta-unsaturated sulfones by base-catalysed elimination of a 2,3-epoxy sulfone is also described.