A mild and efficient reaction of the Bestmann–Ohirareagent with N-unprotected isatin-derived olefins has been developed for the selective synthesis of spiro-pyrazoline-oxindoles and tricyclic pyrazoles. The reaction features an attractive product-selectivity depending on the substituent on isatin-derived olefin. Treatment of 3-aryl/alkylideneoxindoles with BOR afforded spiropyrazoline-oxindoles, whereas
A survey of Lewis acids was conducted to facilitate the formation of arylidenethiohydantoins. The use of indium(III) triflate shows significant advantages in facilitating this reaction. In most examples, the Lewis acid promoted catalysis gave shorter reaction times, higher conversion, and better purity profiles as compared to the traditional uncatalyzed reactions.
Highly Enantioselective and Organocatalytic α-Amination of 2-Oxindoles
作者:Liang Cheng、Li Liu、Dong Wang、Yong-Jun Chen
DOI:10.1021/ol901405r
日期:2009.9.3
chiral carbon center was generated by asymmetric amination of N-unprotected 2-oxindoles with azodicarboxylate catalyzed by commercial biscinchona alkaloids in good to excellent yields with high enantioselectivities.
Drug-like spirocyclic scaffolds have been prepared by fusing fullyfunctionalizedpyrrolidine with oxindoles in an approach based on 1,3-dipolar cycloaddition. Reaction between aziridine and 3-ylideneoxindole generated diverse spirooxindole-pyrrolidines in good yield (up to 95%) with high diastereoselectivity (up to >20:1). The reaction also proceeded smoothly with several other synthetically useful