Hetero Diels−Alder Reactions of 1-Amino-3-siloxy-1,3-butadienes under Strictly Thermal Conditions
作者:Yong Huang、Viresh H. Rawal
DOI:10.1021/ol006404d
日期:2000.10.1
The hetero Diels-Alderreaction of 1-amino-3-siloxy-1,3-butadiene (1a) with a range of unactivated aldehydes proceeds readily under remarkably mild conditions: at room temperature and in the absence of Lewis acid catalysts. The cycloadducts are formed in good yields and can be converted directly to the corresponding dihydro-4-pyrones using acetyl chloride. Ketones and imines are also reactive in hetero
The present invention relates to a process for stereoselective cycloaddition reactions which generally comprises a cycloaddition reaction between a pair of substrates, each either chiral or prochiral, that contain reactive &pgr;-systems, in the presence of a non-racemic chiral catalyst, to produce a stereoisomerically enriched product. The present invention also relates to novel asymmetric catalyst complexes comprising a metal and an asymmetric tridentate ligand.