1.
J Org Chem
; 86(3): 2385-2405, 2021 02 05.
Article
in English
| MEDLINE
| ID: mdl-33423495
ABSTRACT
An efficient pathway toward a novel class of trifluoromethyl building blocks was elaborated. The reaction of α-CF3-enamines with arylaldehydes resulted in direct synthesis of α,ß-diaryl-CF3-enones isolated in up to 93% yield as E-isomers. The possible reaction mechanism was proposed using the Zimmerman-Traxler model. The reaction of α,ß-diaryl-CF3-enones with hydrazines opens a novel pathway to trifluoromethylated pyrazolines. Oxidation of pyrazolines with DDQ opened access to totally regioselective preparation of 3-CF3-pyrazoles isolated in high yield. Using this strategy, 4-arylated derivatives of known drugs Celebrex, Mavacoxib, and SC-560 can be synthesized.