Diastereoselective Synthesis of β‐Amino‐α‐(trifluoromethyl) Alcohols from Homochiral α‐Dibenzylamino Aldehydes

Homochiral α‐dibenzylamino aldehydes, prepared from the corresponding α‐amino acids, react with trimethyl(trifluoromethyl)silane in THF at 0 °C to afford, in good yields and dr , β‐amino‐α‐(trifluoromethyl) alcohols; anti diastereomers were formed as major products in the trifluoromethylation reaction whereas syn diastereomers were obtained as single isomers in a two‐step procedure. Swern oxidation of the mixtures formed in the trifluoromethylation leads to the corresponding α‐dibenzylamino trifluoromethyl ketones which undergo diastereoselective reduction with sodium borohydride. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)