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[摘要]：The diastereoselective nucleophilic trifluoromethylation of a range of ketoamides I (R1 = R2 = Me; R1 = H, R2 = Ph; R3 = Me, OMe; R4 = Et, Ph, 2-MeOC6H4, 3,5-F2C6H3, 2-thienyl, cyclopropyl, etc.) derived from L-tartaric acid has been studied. TMSCF3 in the presence of a catalytic amt. 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 a-trifluoromethylated a-alkoxyaldehydes II (R5 = H2C:CHCH2, PhCH2). This procedure was applied to the prepn. of a series of enantiopure aryl, heteroaryl, and alkyl a-trifluoromethyl-a-alkoxyaldehydes. |
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