One‐Pot Synthesis of Novel α,β‐Dichloro‐β‐trifluoromethylated Enones and Their Application to the Synthesis of Trifluoromethylated Heterocycles.

Abstract

One-Pot Synthesis of Novel α,β-Dichloro-β-trifluoromethylated Enones and TheirApplication to the Synthesis of Trifluoromethylated Heterocycles. -Treatment of Weinreb benzamides (II) with trifluoropropynyllithium (I) and subsequent quenching with trifluoromethanesulfonyl chloride afford the α,β-dichlorinated enones (III) together with the monochlorinated derivatives (IV). The formation of enones (III) proceeds likely via a chloroallenyl amine intermediate. Cyclization reactions between enone (IIIa) and amidines (V) or hydrazines (IX) are successful to provide the trifluoromethylated chloropyrimidines (VI) and chloropyrazoles (X). The functionality of the heterocyclic ring system (VI) is utilized by microwave-assisted coupling reactions of (VI) with allyl-and phenylstannanes (VII). -(JEON, S. L.; KIM, J. K.; SON, J. B.; KIM, B. T.; JEONG*, I. H.; J. Fluorine Chem. 128 (2007) 2, 153-157; Dep. Chem., Yonsei Univ., Wonju 220-710, S. Korea; Eng.) -H. Hoennerscheid