Through Direct Vinylogous Conjugate Additions
Wen Zhang, Davin Tan, Richmond Lee, Guanghu Tong, Wenchao Chen, Baojian Qi, Prof. Dr. Kuo‐Wei Huang, Prof. Dr. Choon‐Hong Tan and Prof. Dr. Zhiyong Jiang
Angewandte Chemie International Edition, 2012, 51, 10069–10073 (Highlighted in organic-chemistry.org; http://www.organic-chemistry.org/Highlights/2013/22July.shtm).
Abstract: The strength of the weak: An L‐tert‐leucine‐derived amine–thiourea catalyst (see scheme, green box) promotes the asymmetric vinylogous conjugate addition reaction between γ‐aryl‐ and alkyl‐substituted butenolides with the butenamides and enoates shown. Computational studies show the preference for the observed stereochemistry is a result of favourable weak non‐bonding interactions, which stabilize the transition state.
Paper download: https://doi.org/10.1002/anie.201205872