Simple and Efficient One-Step Synthesis of a Highly Enantioselective Catalyst 3,3′-Di(pyrrolidinylmethyl)-H 8 BINOL.

A concise one-step synthetic method was developed to prepare (S)-3,3′-di(pyrrolidinylmethyl)-H8BINOL via Mannich-type reaction. Under the optimal reaction conditions, the yield reached 83% (by recrystallization) and 93% (by column chromatography). This new procedure has reduced the molar ratio of pyrrolidine/paraformaldehyde/(S)-H8BINOL from 58:58:1 to 3:3:1, which simplified the previously reported two-step reaction to a one-step reaction with no need for laborious operations such as cooling and solvent degassing, and avoided discharging a large amount of dioxane-containing waste water. [ABSTRACT FROM AUTHOR]