An Enzymatic Approach to the Desymmetrization of Disubstituted Pyrrolines

The enzymatic desymmetrization of 2,2- and 2,5-disubstituted pyrroline compounds is reported in a procedure which gives access to both enantiomers in excellent enantiomeric excess and good yield. The enzyme reaction precursors are formed easily from two readily available substituted pyrroles using both ammonia (Na/NH3) and ammonia-free (Li/DBB) Birch reduction conditions.