Two-step synthesis of vicinal trifluoromethyl primary amines from α-(trifluoromethyl)styrenes and phthalimide.

A novel two-step synthesis of ß-trifluoromethyl primary amines from readily available α-(trifluoromethyl)styrenes and phthalimide is developed. The first step involves a hydroamination between α-(trifluoromethyl)styrenes and phthalimide (PhthNH) with the assistance of a base. Next, the hydrazinolysis of the resulting N-(ß-trifluoromethyl-ß-arylethyl)phthalimides with hydrazine hydrate affords the desired N-(ß-trifluoromethyl-ß-arylethyl)amines.

Solvent-free base-controlled addition reaction of H-phosphonates and H-phosphine oxides to α-CF3 styrenes: facile synthesis of ß-CF3-substituted phosphonates and phosphine oxides.

A practical and efficient solvent-free synthesis of ß-trifluoromethyl-substituted phosphonates and phosphine oxides via hydrophosphonylation and hydrophosphinylation of α-(trifluoromethyl)styrenes with H-phosphonates and H-phosphine oxides, respectively, was developed. The reaction proceeded smoothly within 2 h at room temperature without the cleavage of the rather fragile C-F bond in α-(trifluoromethyl)styrenes and afforded a wide variety of structurally diverse and valuable ß-trifluoromethyl-containing phosphonates and phosphine oxides in moderate to good yields. This protocol features mild conditions, wide substrate scope, simple manipulation, and excellent functional group compatibility.

Controllable Synthesis of Trifluoromethyl- or gem-Difluorovinyl-containing Analogues of Neonicotinoids by the Reaction of α-(Trifluoromethyl)styrenes with 2-Nitroimino-imidazolidine.

A simple and straightforward addition or defluorination of α-(trifluoromethyl)styrenes with 2-nitroimino-imidazolidine (2a), 2-(nitromethylene)imidazolidine (2b), 2-cyanoimino-thiazolidine (2c), and (E)-1-methyl-2-nitroguanidine (2d), in a controlled manner, was developed. The hydroamination of α-(trifluoromethyl)styrenes with 2a, 2b, 2c, and 2d was completed in the presence of DBN at room temperature within 0.5-6 h, affording structurally diverse ß-trifluoromethyl-ß-arylethyl analogues of neonicotinoids in moderate to good yields. The γ,γ-difluoro-ß-arylallyl analogues of neonicotinoids were also successfully synthesized via defluorination of α-(trifluoromethyl)styrenes, with 2a and 2c using NaH as base at an elevated temperature together with a prolonged reaction time of 12 h. The method features simple reaction setup, mild reaction conditions, broad substrate scope, high functional group compatibility, and easy scalability.

Highly Regioselective Synthesis of N-ß-trifluoromethyl 2-pyridones via anti-Markovnikov Hydroamination of α-(trifluoromethyl)styrenes with 2-pyridones.

A novel and facile method for the synthesis of N-ß-CF3 -substituted 2-pyridones via hydroamination of α-(trifluoromethyl)styrenes with 2-pyridones was described. The reaction proceeded smoothly at room temperature, affording a variety of N-(ß-trifluoromethyl-ß-arylethyl)pyridin-2(1H)-ones in moderate to good yields with excellent N-regioselectivity.