Chiral cyclopropenimines are a highly effective new class of enantioselective Brnsted base catalysts - the so-called “superbases” for enantioselective organocatalysis. Due to the prevalence of chemical reactions involving proton transfer as a key mechanistic event, Brnsted bases have become indispensable tools for the practice of organic synthetic chemistry, capable of catalyzing proton transfer reactions enantioselectively for the production of optically enriched products. Catalyst is stored as co-salt for stability. Conversion of the HCl salt to free catalyst requires a simple wash with aqueous base. This is one of a suite of Brnsted catalysts reported by
Tristan Lambert and coworkers available through Sigma-Aldrich.
