Alkylation of Ketene Silyl Acetals with Nitroolefins Mediated by Sterically Encumbered Lewis Acids
作者:John A. Tucker、Terrance L. Clayton、Donald M. Mordas
DOI:10.1021/jo9624004
日期:1997.6.1
procedures for the corresponding reaction of esters suffer from important limitations such as modest yields, lack of demonstrated generality, inconveniently low reaction temperatures, and/or the use of a large excess of one of the two reactants. In the present work, we examined the efficacy of a series of Lewisacid catalysts for the alkylation of ketenesilylacetals with nitroolefins. Previously reported
Enantioselective Organocatalytic Michael−Wittig−Michael−Michael Reaction: Dichotomous Construction of Pentasubstituted Cyclopentanecarbaldehydes and Pentasubstituted Cyclohexanecarbaldehydes
作者:Bor-Cherng Hong、Roshan Y. Nimje、Cheng-Wei Lin、Ju-Hsiou Liao
DOI:10.1021/ol1030487
日期:2011.3.18
reagent) to nitroalkenes, followed by a reaction with ethyl formylformate and cinnamaldehydes, or formaldehyde and cinnamaldehydes, provided the respective pentasubstituted cyclopentanecarbaldehydes bearing a quaternary carbon center and pentasubstituted cyclohexanecarbaldehydes having five contiguous stereocenters with excellent enantioselectivities (up to >99% ee).