The asymmetric allylation of glycine iminoesters has been accomplished through a synergistic Pd/Cu catalyst system, affording a range of α-substituted α-amino acids in high yields and with excellent enantioselectivities (88 → 99% ee). The introduction of a Cu-P,N-metallocenyl complex-activated glycine iminoester to the chiral palladium-catalyzedallylic allylation process is crucial owing to its high
Ru-Centered coordination complexes as a new phase transfer catalyst for alkylation of enolates and Michael additions
作者:Dimitrios Tzalis、Paul Knochel
DOI:10.1016/s0040-4039(99)00587-0
日期:1999.5
A novel phasetransfercatalysis based on a Ru(II)-polypyridyl complex 1 allows the fast alkylation of enolates and Michael additions under very mild conditions.
A short protocol for the practical scale synthesis of several Ï-borono-α-amino acids is described via the alkylation of benzophenone glycinimines with various electrophiles.
N-Heterocyclic olefins as efficient phase-transfer catalysts for base-promoted alkylation reactions
作者:Marcus Blümel、Reece D. Crocker、Jason B. Harper、Dieter Enders、Thanh V. Nguyen
DOI:10.1039/c6cc03771b
日期:——
N-Heterocyclic Olefins (NHOs) have very recently emerged as efficient promoters for several chemical reactions due to their strong Bronsted/Lewis basicities. Here we report the novel application of NHOs as efficient...
Novel preparation of chiral α-amino acids using the Mitsunobu–Tsunoda reaction
作者:Anaïs F. M. Noisier、Craig S. Harris、Margaret A. Brimble
DOI:10.1039/c3cc44717k
日期:——
An efficientsynthesis of racemic or opticallyactive alpha-amino acids by modified-Mitsunobu alkylation of a racemic or chiral glycine template from alcohols was developed. Libraries of amino acids were prepared in moderate to good yield with good to high enantioselectivity. This simple method widens the scope for preparation of structurally diverse amino acids.