反应详情

Several articles have described the condensation of substituted benzaldehyde derivatives with chloroform in the presence of various bases to produce the corresponding α-(trichloromethyl)benzyl alcohols. In the case of nitrosubstituted benzaldehydes, only Cannizzaro reaction products are obtained when powdered potassium hydroxide is used as the base without solvent. Phase transfer conditions produce a mixture of nitrobenzoic acid, nitrobenzyl alcohol, and trichloromethylnitrobenzyl alcohol. Potassium t-butoxide in liquid ammonia at -75° C. has been reported to effect the desired condensation to form trichloromethyl-3-nitrobenzyl alcohol in 72% yield (Ya. G. Bal'on, V. E. Paranyuk, and M. D. Shul'man, Zh. Obsch. Khim., 44, 2633 (1974)). Under the same conditions potassium hydroxide or calcium oxide in dimethyl sulfoxide gives 5-10% lower yields. The generation of trichloromethide anion in solution from the decomposition of trichloroacetic acid in dimethyl sulfoxide has been used to prepare trichloromethyl-4-nitrobenzyl alcohol in 60% yield (P. J. Atkins et al., J. Chem. Soc., Chem. Comm., 1983, pp. 283-4).

1. customare obtained when
2. customPhase transfer conditions produce
3. customat -75° C.
4. customcondensation