Asymmetric organocatalytic Michael-type reaction of phosphorus ylides to nitroolefins: synthesis of γ-nitro-β-aryl-α-methylene carboxylic esters
作者:Suresh Allu、Sermadurai Selvakumar、Vinod K. Singh
DOI:10.1016/j.tetlet.2009.11.063
日期:2010.1
We report, for the first time, asymmetric organocatalytic Michael-type addition of stabilized phosphorus ylides to nitroolefins mediated by bisthiourea catalyst. Its subsequent reaction with formaldehyde provides γ-nitro-α-methylene carboxylicesters in moderate to good yields and enantioselectivities (up to 63% ee).
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).