Reaction of chiral acryloylhydrazide 5 derived from novel auxiliary 4 with aldehydes in the presence of DABCO affords practical levels (up to 98% de) of beta-hydroxy-alpha-methylene carbonyl derivatives, and high optical purity of both diastereomers of 6a-d and 7a-d can be obtained by changing the solvent.
An effective chiral Lewis acid-catalyzed asymmetric Baylis-Hillman reaction is described. Good to high enantioselectivities were obtained using 3 mol % chiral catalyst. Novel camphor-derived dimerized ligands were prepared from the condensation of (+)-ketopinic acid with the corresponding diamines and hydrazine under acidic conditions. When alpha-naphthyl acrylate was used as a Michael acceptor, the reaction is complete within 20 min with high stereoselectivity and in reasonable chemical yields.
The Morita-Baylis-Hillman (MBH) reaction is one of the most useful and efficient protocols for constructing new carbon-carbon bonds between an activated olefin and electrophiles in the presence of a tertiary amine/phosphine. Herein, we present the use of MBH alcohols, which are obtained from the reaction of nitrostyrenes with aldehydes, as well as acetates and amines derived thereof in several organocatalytic transformations. Densely functionalised MBH adducts can also be used to synthesise substituted heteroaromatic compounds, such as furan, pyrrole, pyrazole and imidazole derivatives.
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