Stereoselective addition reactions of chiral .alpha.-sulfinyl ketimine anions with ene esters. Facile asymmetric synthesis of indolo[2,3-a]quinolizidine and yohimbanoid alkaloids
Stereoselective addition reactions of chiral .alpha.-sulfinyl ketimine anions with ene esters. Facile asymmetric synthesis of indolo[2,3-a]quinolizidine and yohimbanoid alkaloids