The tandem sulfonium ylide formation-[2,3]-sigmatropicrearrangement reaction of chiral non-racemic secondary allylic sulfides, (E)-9 and (Z)-10, is found to proceed with high diastereocontrol. The C-5 stereocenter bearing the sulfide group is essential for high diastereoselectivity in the reaction. Transition state conformers are proposed to explain the high diastereoselectivity in the formation of
Synthesis of enantiomerically pure pyrrolidines by stereospecific cycloaddition of azomethine ylides with enones
作者:M. Pätzel、G. Galley、P.G. Jones、A. Chrapkowsky
DOI:10.1016/s0040-4039(00)73839-1
日期:1993.9
alkoxy or amino substituent in γ-position react with azomethine ylides 3 (obtained from glycine imines) in the presence of DBU/AgOAc giving enantiomerically pure pyrrolidine derivatives 4 in a stereospecific manner.
Asymmetric induction in acyclic michael reactions: Addition of organometallic reagents to enones derived from (R)-glyceraldehyde acetonide
作者:John Leonard、Gary Ryan
DOI:10.1016/s0040-4039(00)95458-3
日期:1987.1
Isopropenyl copper reacts 1,4 with enones derived from glyceraldehyde acetonide with ANTI selectivity, whereas isopropenyl lithium also gives predominantly 1,4 product but with SYN selectivity.
Stereoselective conjugate addition of organolithium and organocopper reagents to δ-oxygenated α,β-unsaturated carbonyl systems derived from glyceraldehyde acetonide
作者:John Leonard、Soad Mohialdin、Darrel Reed、Gary Ryan、Philip A. Swain
DOI:10.1016/0040-4020(95)00875-9
日期:1995.11
Addition reactions of organolithium and Organocopper reagents to δ-oxygenated α,β-unsaturated carbonyls, derived from glyceraldehyde acetonide, have been studied. In most cases there is a strong preference for conjugate addition of the organometallic reagent. Organocopper reagents react with anti stereoselectively, whereas most organolithiumreagents react with syn stereoselectivity, except for phenyllithium
Diastereofacial selectivity of the cycloaddition of diazo compounds to enones
作者:G Galley、M Pätzel、P.G Jones
DOI:10.1016/0040-4020(94)01049-6
日期:1995.2
Chiral α,β-unsaturated γ-alkoxy- or γ-amino-ketones (enones) 1 react with diazocompounds in a stereoselective manner affording conjugated Δ2-pyrazolines 5 and 6. In all cases syn-selectivity for the cycloaddition was observed. The diastereomeric ratio is improved at lower temperatures, but no significant influence of high pressure is observed. Carrying out this reaction with (E) and (Z) derivatives