Control of diastereofacial selectivity in the nucleophilic epoxidation of γ-oxygenated-α,β-unsaturated sulphones
摘要:
Epoxidation of gamma-oxygenated-alpha,beta-unsaturated sulphones 4-8 with lithium t-butyl hydroperoxide proceeds with moderate to high diastereoselectivity to give 2-phenylsulphonyl oxiranes 9-13. The sense of diastereoselectivity is dependent on the steric bulk of the alkyl substituent at the gamma-centre.
Homochiral 2,3-epoxy sulfides as precursors to -γ-hydroxy-α,β-unsaturated sulfoxides and sulfones.
摘要:
The synthesis of E-gamma-hydroxy-alpha,beta-unsaturated sulfoxides and sulfones from the corresponding homochiral 2,3-epoxy sulfides is described with excellent control of double bond geometry and stereochemistry at both the sulfoxide and secondary alcohol chiral centres.
Homochiral 2,3-epoxy sulfides as precursors to -γ-hydroxy-α,β-unsaturated sulfoxides and sulfones.
作者:Andrew D. Westwell、Christopher M. Rayner
DOI:10.1016/s0957-4166(00)86205-9
日期:1994.3
The synthesis of E-gamma-hydroxy-alpha,beta-unsaturated sulfoxides and sulfones from the corresponding homochiral 2,3-epoxy sulfides is described with excellent control of double bond geometry and stereochemistry at both the sulfoxide and secondary alcohol chiral centres.
A new method for the dehydration of β-hydroxy sulfones: synthesis of (E,S)-γ-hydroxy-α,β-unsaturated sulfones and (S)-ε-hydroxy-(E,E)-α,γ-dienyl sulfones
Optically active (E,S)-gamma-hydroxy-alpha,beta-unsaturated sulfones and (S)-epsilon-hydroxy-(E,E)-alpha,gamma-dienyl sulfones have been prepared in a one-pot dehydration procedure from beta,gamma-dihydroxy sulfones and delta,epsilon-dihydroxy allyl sulfones, respectively, via an elimination reaction of the corresponding cyclic sulfites or carbonates formed in situ by treatment with thionyl chloride or carbonyldiimidazole.
Control of diastereofacial selectivity in the nucleophilic epoxidation of γ-oxygenated-α,β-unsaturated sulphones
作者:Richard F.W. Jackson、Stephen P. Standen、William Clegg
DOI:10.1016/s0040-4039(00)92395-5
日期:1991.9
Epoxidation of gamma-oxygenated-alpha,beta-unsaturated sulphones 4-8 with lithium t-butyl hydroperoxide proceeds with moderate to high diastereoselectivity to give 2-phenylsulphonyl oxiranes 9-13. The sense of diastereoselectivity is dependent on the steric bulk of the alkyl substituent at the gamma-centre.
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.