For the first time, monoterpene trifluoromethylated β-hydroxy-benzyl-O-oximes were synthesized in 81-95% yields by nucleophilic addition of the Ruppert-Prakash reagent (TMSCF3) to the corresponding β-keto-benzyl-O-oximes based on (+)-nopinone, (-)-verbanone and (+)-camphoroquinone. Trifluoromethylation has been determined to entirely proceed chemo- and stereoselective at the C=O rather than C=N bond. Trifluoromethylated benzyl-O-oximes were reduced to the corresponding α-trifluoromethyl-β-amino alcohols in 82-88% yields. The structure and configuration of the compounds obtained have been established.
Keywords: Ruppert–Prakash reagent; bornane; chiral amino alcohol; monoterpenoids; pinane; trifluoromethylation.