In an abnormal Grignard reaction of halothane, the primary Grignard reagent reacts with another mole of halothane to give 1-bromo-1-chloro-2, 2, 2-trifluoroethylmagnesium bromide, which in turn reacts with a carbonyl compound to give 1-bromo-1-chloro-2, 2, 2-trifluoroethyl carbinols and their dehalogenation products, 1-chloro-2, 2-difluoroethenyl carbinols. We examined the application of this method to aldehydes and to unsaturated ketones. Aldehydes were much less reactive than ketones, and needed higher reaction temperature. However, elevation of temperature caused dehalogenation of the primary products to 1-chloro-2, 2-difluoroethenyl derivatives. These derivatives were treated with hydrogen fluoride to afford 1-chloro-1-(trifluoromethyl)ethene derivatives. The reaction of α, β-unsaturated ketones mainly gave 1, 2-addition products of the Grignard reagent, while 3-methyl-2-cyclohexenone gave mainly the 1, 4-adducts.
Efficient carboncarbon bond formation with thermally stable 1,1-dihalo-2,2,2-trifluoroethylzinc reagent
作者:Makoto Fujita、Tomoe Morita、Tamejiro Hiyama
DOI:10.1016/s0040-4039(00)84468-8
日期:1986.1
The zinc carbenoids CF3CX2ZnX, prepared from CF3CX3 and zinc powder in dimethylformamide, were found thermally stable to add to aldehyde carbonyls in excellent yields.
Efficient Carbonyl Addition of Polyfluorochloroethyl, -ethylidene, and -ethenyl Units by Means of 1,1,1-Trichloro-2,2,2-trifluoroethane and Zinc
作者:Makoto Fujita、Tamejiro Hiyama
DOI:10.1246/bcsj.60.4377
日期:1987.12
powder in N,N-dimethylformamide and was allowed to add to carbonyls of aldehydes and α-keto esters in excellent yields to give 1-substituted 2,2-dichloro-3,3,3-trifluoro-1-propanols. Employment of excess zinc induced further reductive β-elimination to afford 1-substituted 2-chloro-3,3,3-trifluoropropenes (3) and 1-substituted 2-chloro-3,3-difluoro-2-propen-1-ols (4). Exclusive formation of 3 was achieved