A new chiral Brønsted acid derived from carboxylic acid and a chiral oxazaborolidinium ion (COBI), as an activator, is introduced. This acid was successfully applied as a catalyst for the highly enantioselective protonation/nucleophilic addition of diazoesters with carboxylic acids.
Chiral oxazaborolidinium
ion (COBI)-catalyzed enantioselective
nucleophilic addition reactions of aldimines using tributyltin cyanide
and allyltributylstannane have been developed. Various α-aminonitriles
and homoallylic amines were synthesized in high yield (up to 98%)
with high to excellent enantioselectivity (up to 99% ee). A rational
mechanistic model for the complex of COBI and aldimine is provided
to account for these enantioselective reactions.
A new chiral Brønsted acid derived from carboxylic acid and a chiral oxazaborolidinium ion (COBI), as an activator, is introduced. This acid was successfully applied as a catalyst for the highly enantioselective protonation/nucleophilic addition of diazoesters with carboxylic acids.
The asymmetric unit of the title compound, C9H8O2, contains two independent molecules, both of which are essentially planar (r.m.s. deviations = 0.0294 and 0.0284 Å). The C=C double bond is in an E conformation and the vinylaldehyde groups adopt extended conformations. In the crystal, molecules are linked by O—H⋯O hydrogen bonds, forming infinite chains parallel to [101].
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.