The reactions of 2,3-epoxyaldehydes with methoxymethylenetriphenylphosphorane. Enantioselective syntheses of (E)-4-hydroxyalk-2-enals
作者:Libing Yu、Zhiqin Wang
DOI:10.1039/c39930000232
日期:——
The reactions of 2,3-epoxyaldehydes with methoxymethylenetriphenylphosphorane in tetrahydrofuran provide directly (E)-4-hydroxy-2-enals with the retention of configuration.
Asymmetric Formal <i>trans</i>-Dihydroxylation and <i>trans</i>-Aminohydroxylation of α,β-Unsaturated Aldehydes via an Organocatalytic Reaction Cascade
study demonstrates the first formal asymmetric trans-dihydroxylation and trans-aminohydroxylation of alpha,beta-unsaturated aldehydes in an organocatalytic multibond forming one-pot reactioncascade. This efficient process converts alpha,beta-unsaturated aldehydes into optically active trans-2,3-dihydroxyaldehydes and trans-3-amino-2-hydroxyaldehydes with the aldehyde moiety protected as an acetal. The
A new and efficient catalytic isomerization of cis - and trans -epoxides
作者:Ching-Yu Lo、Sitaram Pal、Arjan Odedra、Rai-Shung Liu
DOI:10.1016/s0040-4039(03)00465-9
日期:2003.4
We report new ruthenium-catalyzed cis–trans isomerization of various functionalized epoxides. Enantiospecific isomerization of chiral epoxides is achieved without loss of enantiopurity, and epimerization occurs only at the epoxide carbon of the activating group.
Herein, we report a catalytic and stereospecific method for the preparation of enantioenriched α‐hydroxy cyclopropylboronates with control in four contiguous stereocenters. The reaction involves the borylation of readily available allylic epoxides using an inexpensive Cu(I) salt and a commercially available phosphine ligand. High diastereocontrol is achieved and different diastereomers can be selectively
Borylation and rearrangement of alkynyloxiranes: a stereospecific route to substituted α-enynes
作者:Ruben Pomar Fuentespina、José Angel Garcia de la Cruz、Gabriel Durin、Victor Mamane、Jean-Marc Weibel、Patrick Pale
DOI:10.3762/bjoc.15.141
日期:——
cis or trans-alkynylated oxiranes in good to excellent yields by a one-pot cascade process. The procedure relies on oxirane deprotonation, borylation and a stereospecificrearrangement of the so-formed alkynyloxiranyl borates. This stereospecific process overall transfers the cis or trans-stereochemistry of the starting alkynyloxiranes to the resulting 1,3-enynes.