Synthesis of Three‐, Five‐, and Six‐Membered Heterocycles Derived from New β ‐Amino‐ α ‐(trifluoromethyl) Alcohols

Nucleophilic trifluoromethylation of α ‐imino ketones 2 , derived from arylglyoxal, with Ruppert – Prakash reagent (CF 3 SiMe 3 ) offers a convenient access to the corresponding O ‐silylated β ‐imino‐ α ‐(trifluoromethyl) alcohols. In a ‘one‐pot’ procedure, by treatment with NaBH 4 , these products smoothly undergo reduction and desilylation yielding the expected β ‐amino‐ α ‐(trifluoromethyl) alcohols 4 . The latter were used as starting materials for the synthesis of diverse trifluoromethylated heterocycles, including aziridines 5 , 1,3‐oxazolidines 8 , 1,3‐oxazolidin‐2‐ones 9 , 1,3,2‐oxazaphospholidine 2‐oxides 10 , 1,2,3‐oxathiazolidine 2‐oxides 11 , and morpholine‐2,3‐diones 12 . An optically active 5‐(trifluoromethyl)‐substituted 1,3‐oxazolidin‐2‐one 9g was also obtained.