Lipase-Catalyzed Synthesis of Optically Active N,N,N,-Trimethylethanaminium α-Tocopherol Analog MDL-73404

Optically active 3,4-dihydro-6-hydroxy-N,N,N,2,5,7,8,-heptamethyl-2H-1-benzopyran-2-ethanaminium 4-methylbenzenesulfonate MDL-73404 was synthesized by kinetic resolution of racemic chromanethanols with lipase. The unnecessary (R)-chromanethanol as by-product of resolution was inverted to the (S)-isomer that could be treated as substrate for repeated lipase-catalyzed resolution.