Exploration on asymmetric synthesis of flavanone catalyzed by (S)-pyrrolidinyl tetrazole.

An improved method of the synthesis of flavanones catalyzed by pyrrolidine and BF(3) ·Et(2) O has been developed and a lot of flavanones could be easily synthesized via this method. The asymmetric synthesis of flavanone from benzaldehyde and 5-fluoro-2-hydroxyacetophenone has been studied and flavanone with moderate enantioselectivity was obtained in one step.