The diastereoselective nucleophilic trifluoromethylation of a range of ketoamides derived from L-tartaric acid has been studied. TMSCF3 in the presence of a catalytic amount of K2CO3 in DMF has been identified as the conditions leading to the highest diastereoselectivities. A sequential one-pot reaction trifluoromethylation-etherification of the trifluoromethylcarbinol has been developed. Only one further one-pot reaction, ketal hydrolysis-oxidative cleavage, led to the final alpha-trifluoromethylated alpha-alkoxyaldehydes. This procedure was applied to the preparation of a series of enantiopure aryl, heteroaryl, and alkyl alpha-trifluoromethyl-alpha-alkoxyaldehydes.

We report herein the synthesis of enantiomerically pure 2-phenyl- and 2-ethyl-2-trifluoromethylaziridines by Mitsunobu-type cyclisation of the corresponding N-protected amino alcohols, and our results regarding their ring opening with selected nucleophiles. Under basic conditions, N-tosyl aziridines have been regioselectively opened at the less hindered carbon. Under acidic conditions, the regioselectivity of the attack depends on the nature of the substituent at C-2 and on the nitrogen protecting group.