1. CDCl 3, for mixture of A and B isomers: ? 20;P Nmr;121 ?Hz
2. The general procedure was followed using 48 mg of thiohydrazide 1b. Purification by column chromatography (eluent CH 2 Cl 2 -MeOH, 150 : 1) afforded product (mixture of diastereomers A/B, 1 : 1) as a pale yellow solid (60 mg;C