Mitsunobu cyclodehydration of N-pivaloyl-2-aminophenethyl alcohol for asymmetric synthesis of trans-2,3-disubstituted indolines

Highly enantioenriched trans-2,3-disubstituted indolines have been prepared by Mitsunobu cyclodehydration of the amino alcohols obtained from (−)- or (+)-sparteine-mediated lithiation-substitution of ortho-alkyl substituted N-pivaloylanilines. Optimized cyclodehydration conditions are described, from which the combination of DEAD and PBu3 in CH3CN provides the best results.