Use of an Ephedrine Alkoxide to Mediate Enantioselective Addition of an Acetylide to a Prochiral Ketone: Asymmetric Synthesis of the Reverse Transcriptase Inhibitor L-743,726.

Article abstract of DOI:10.1016/0040-4039(95)01955-H

The asymmetric synthesis of L-743,726 was achieved in six steps with an overall yield of 31 percent.The asymmetry was introduced using a lithiated ephedrine to mediate acetylide addition to a trifluoromethyl ketone with an enantiomeric excess of 96-98 percent.