Highly Enantioselective Synthesis of a 2,3‐Dihydroindole Mediated by N‐Methylephedrine

Cyclization of the prochiral starting material 1 to the almost enantiomerically pure product 2, R = n-Pr, proceeded in the presence of the chiral catalyst formed from n-BuLi and N-methylephedrine 3. (+)-3 leads to (−)-2 and (−)-3 to (+)-2 (>95%ee). However, this result was not achieved with other substituents R in 1.