Juliá–Colonna stereoselective epoxidation of some α,β-unsaturated enones possessing a stereogenic centre at the γ-position: synthesis of a protected galactonic acid derivative
Diastereo- and enantioselective synthesis of α,β-epoxyketones using aqueous NaOCl in conjunction with dihydrocinchonidine derived phase-transfer catalysis at room temperature. Scope and limitations
作者:Barry Lygo、Stuart D. Gardiner、Michael C. McLeod、Daniel C. M. To
DOI:10.1039/b706546a
日期:——
In this paper we present studies into the scope and limitations of asymmetric PTC epoxidation of enones and the oxidationâepoxidation of allylic alcohols using aqueous NaOCl in conjunction with a dihydrocinchonidine derived quaternary ammoniumsaltcatalyst.
A study of conjugate addition to a γ,δ-dioxolanyl-α,β-unsaturated ester
作者:Guoxia Han、Victor J. Hruby
DOI:10.1016/s0040-4039(01)00719-5
日期:2001.6
Diastereoselective phenylcuprate addition to (S)-3-(2,2-dimethyl-1,3-dioxolan-4-yl)-trans-2-propenoate has been achieved in the presence of lithium bromide, copper(I) cyanide, trimethylsilyl chloride and dimethylsulfide cocatalysts.
Overcoming intrinsic diastereoselection using polyleucine as a chiral epoxidation catalyst
作者:Peter C. Ray、Stanley M. Roberts
DOI:10.1016/s0040-4039(98)02689-6
日期:1999.2
The use of polyleucine in the diastereoselective, catalyst-controlled epoxidation of enantiomerically pure gamma-heterosubstituted-alpha,beta-unsaturated ketones (1), to yield the corresponding alpha,beta-epoxy-gamma,delta-(isopropylidene)dioxy carbonyl compounds, is described. (C) 1999 Elsevier Science Ltd. All rights reserved.
Trifluoroacetic Anhydride Promoted Tandem Conjugate Addition of Boronic Acids/Acetal Ring Opening
作者:Silvia Roscales、Aurelio G. Csákÿ
DOI:10.1021/ol300272j
日期:2012.3.2
A new stereoselective tandem reaction consisting of the metal-free conjugate addition of boronic acids followed by an intramolecular ringopening of a cyclic acetal has been disclosed. Optically pure polysubstituted tetrahydropyrans have been synthesized diastereoselectively by this new reaction. Two new C–C bonds and up to three stereocenters are formed in a single step, allowing the generation of