Synthesis of trichloromethyl carbinols
Trihaloacetic acids can been converted to trichloromethyl and tribromomethyl ketones in good yield by a catalyzed reaction with aldehydes followed by oxidation. A coupling of organozinc intermediates with trichloroacetyl chloride gives trichloromethyl ketones.
E. J. Corey, J. O. Link, Y. Shao, Tetrahedron Lett., 1992, 33, 3435-3438.
In a synthesis of 2,2,2-trichloromethylcarbinols, a combination of sodium trichloroacetate in the presence of malonic acid enables an efficient transformation of electron deficient aldehydes in DMSO, whereas electron-rich aldehydes did not require the addition of malonic acid. By performing this decarboxylative reaction in continuous flow, scale-up of the reaction could be achieved with a simple and safe setup.
A. B. Jensen, A. T. Lindhardt, J. Org. Chem., 2014, 79, 1174-1183.
Versatile trichloromethyl carbinols can be prepared in one pot from primary alcohols by treatment with Dess-Martin periodinane in CHCl3 followed by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD).
M. K. Gupta, Z. Li, T. S. Snowden, J. Org. Chem., 2012, 77, 4854-4860.
A scalable procedure for the synthesis of TMS-protected-2,2,2-trichloromethylcarbinols and 2,2,2-trichloromethylcarbinols employs an in situ generation and reaction of trimethyl(trichloromethyl)silane (CCl3-TMS). The procedure avoids the exposure of the carbonyl compounds to the strongly basic conditions typically used for this transformation and also avoids isolation of the difficult-to-handle CCl3-TMS.
K. E. Henegar, R. Lira, J. Org. Chem., 2012, 77, 2999-3004.