作者:Ashok K. Basak、Naoyuki Shimada、William F. Bow、David A. Vicic、Marcus A. Tius
DOI:10.1021/ja103028r
日期:2010.6.23
An organocatalytic asymmetric Nazarov cyclization of diketoesters that proceeds by means of a dual activation mechanism has been developed. Screening of a number of catalysts led to a new thiourea that incorporates a primary amino group. The method gives rise to cyclic products with two adjacent quaternaryasymmetriccarbon atoms, one of which is an all-carbon stereocenter, with complete or nearly
Stereoselective Synthesis of Ethyl (<i>Z</i>)-3-Aryl-2-ethoxyacrylates: Wittig Reaction of Diethyl Oxalate
作者:R. Alan Aitken、Gail L. Thom
DOI:10.1055/s-1989-27446
日期:——
The Wittig olefination of diethyl oxalate with a variety of arylmethylenetriphenylphosphoranes 1 proceeds readily in tetrahydrofuran at room temperature to give ethyl 3-aryl-2-ethoxyacrylates 2 with a Z/E selectivity of ≥10:1.