Organocatalytic Enantioselective aza-Michael Additions of N-Heterocycles to α,β-Unsaturated Enones
作者:Jian Lv、Hao Wu、Yongmei Wang
DOI:10.1002/ejoc.200901227
日期:2010.4
A procedure for enantioselectiveorganocatalytic conjugate additions of a variety of N-heterocycles to α,β-unsaturated enone systems is presented. The reactions are efficiently catalyzed by salts of 9-amino-9-deoxy-epiquinine (3d). Cyclic, acyclic, and aromatic enones can be used in reactions with 1H-benzotriazole (1a) or 5-phenyltetrazole derivatives 12, providing the Michael addition products in
Résumé The catalyst-free reactions of activated alkenes with primary and secondary amines were investigated leading to various mono- and di-hydroamination products, the latter being rare and original. These reactions were shown to depend first on the strength of the nucleophile. Temperature and steric hindrance of the reagents were the other key factors controlling the selectivity of these aza-Michael reactions. In spite of their poor nucleophilicities, some N-heterocyclic amines could react with different activated alkenes affording valuable intermediates. Such results tended to demonstrate the hydrogen-bonding interactions between activated alkenes and poly-nitrogen aromatic cycles may control these concerted or fully conjugate aza-Michael additions. Supplementary Materials: Supplementary material for this article is supplied as a separate file: mmc1.doc
E-factor minimized protocols for the polystyryl-BEMP catalyzed conjugate additions of various nucleophiles to α,β-unsaturated carbonyl compounds
作者:Simona Bonollo、Daniela Lanari、Julie M. Longo、Luigi Vaccaro
DOI:10.1039/c1gc16088e
日期:——
Efficient protocols for the addition of carbon-, sulphur- and nitrogen-nucleophiles to α,β-unsaturated carbonylcompounds catalyzed by PS-BEMP have been reported. The adoption of solvent-free conditions (SolFC) was crucial for improving the efficiency of all the processes, while by using an organic reaction medium poor results were obtained. Addition reactions were performed by using equimolar amounts
A combination of gold chloride organometallic complex and a silver salt was used to catalyze intermolecular hydroamination of activated alkenes, i.e aza-Michael reactions. The gold-catalyzed reactions of activated alkenes with nitrogen substrates were investigated and found to afford various mono- and dihydroamination products, the latter being rare and original. After flash chromatography, gold NHC