Silicon Lewis Acid Catalyzed [3+2] Cycloaddition Reactions of Hydrazones/Cyclopentadiene: Mild Access to Pyrazolidine Derivatives
作者:Alexandru Zamfir、Sebastian Schenker、Walter Bauer、Timothy Clark、Svetlana B. Tsogoeva
DOI:10.1002/ejoc.201100206
日期:2011.7
A first and fairly mild metal-free catalytic route was developed for the [3+2] cycloadditions of different N-acylhydrazones to cyclopentadiene, providing the synthetically andbiologically important five-membered cyclic compounds pyrazolidines. The reaction was successfully conducted in high yields (up to 99 %) with high diastereoselectivities (up to 98:2 dr) by using catalytic amounts of TMSOTf (trimethylsilyl