Optically active 4-amino-4-aryl-5,5,5-trifluoropentan-2-ones: Versatile reagents for synthesis of chiral 4-trifluoromethyl-3,4-dihydroazin-2-ones

A cyclocondensation of disubstituted (thio)ureas and isocyanates derived from enantiomerically enriched 4-amino-4-aryl-5,5,5-trifluoropentan-2-ones affords a novel synthetic access to chiral 4-trifluoromethyl-substituted 3,4-dihydropyrimidin-2(1H)-(thi)ones and 3,4-dihydro-1,3-oxazin-2-ones, respectively.