1: 1) acetone, 2) acetone, reflux 2: 96 percent / Bu3SnH, AIBN / benzene / 0.5 h / 80 °C View Scheme

(2S,3R)-3-methyl-2-phenyl-3,4-dihydro-2H-benzo[4,5]thiazolo[3,2-a]pyrimidine; sodium sulfate; N-ethyl-N,N-diisopropylamine in toluene T=-40°C; 11 h; Resolution of racemate; optical yield given as percent eeenantioselective reaction;

[bis(acetoxy)iodo]benzene; (1S,4S)-4-Bn-1-nBu-AZADOH in dichloromethane T=-5°C; Resolution of racemateInert atmosphere; optical yield given as percent eeenantioselective reaction;

potassium dichromate; sulfuric acid