Preparation of (S)-(+)- and (R)-(-)-8-trifluoromethanesulfonyloxymianserin

8-Trifluoromethanesulfonyloxymianserin (3) was synthesized. Its enantiomers were separated by means of HPLC using a chiral stationary phase in the semipreparative mode (100 mg scale) in greater than or equal to 99% optical purity. Reduction of the enantiomers of 3 under catalytic hydrogenation conditions gave the mianserin enantiomers in high purity. The absolute configuration of the enantiomers of 3 were assigned by comparing their respective optical rotations with those of the mianserin enantiomers.