Catalytic Asymmetric Intermolecular Stetter Reaction of Glyoxamides with Alkylidenemalonates
摘要:
An asymmetric intermolecular Stetter reaction of glyoxamide and alkylidenemalonates has been developed. Catalyzed by a novel N-heterocyclic carbene, the Stetter adducts are formed in good yield and excellent enantioselectivity. The presence of a sensitive epimerizable stereocenter is tolerated under these mildly basic reaction conditions if a bulky amine base is used. The products may be further elaborated to provide synthetically useful intermediates.
Phase-Transfer-Catalyzed Asymmetric Conjugate Cyanation of Alkylidenemalonates with KCN in the Presence of a Brønsted Acid Additive
作者:Yan Liu、Seiji Shirakawa、Keiji Maruoka
DOI:10.1021/ol400143m
日期:2013.3.15
Highly enantioselective conjugate cyanation of alkylidenemalonates with KCN was achieved under mild phase-transfer conditions with a bifunctional phase-transfer catalyst. The effect of Brønstedacid additives was examined based on the hypothetical catalytic cycle, and the Brønstedacid additive was found to be essential to promote the conjugate cyanation efficiently.