New conditions for the preparation of trimethylsilyl-protected 2,2,2-trichloromethylcarbinols 2 from aldehydes and ketones are reported. Compounds 2, which are important intermediates in organic synthesis, were obtained in excellent yields by use of a combination of trichloromethyltrimethylsilane (TMSCCl3), and a catalytic amount of sodium formate (HCOONa) in dimethylformamide (DMF). Substrates bearing highly sensitive protecting groups have been successfully subjected to our conditions. We also describe a one-pot procedure that gives direct access to 2,2,2-trichloromethylcarbinols 3. This methodology avoids the use of strong bases usually required for the synthesis of 3 (Wyvratt et al. J. Org. Chem. 1987, 52, 944; Aggarwal and Mereu, J. Org. Chem. 2000, 65, 7211).
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http://dx.doi.org/10.1021/jo070180w | DOI Listing |
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