Synthesis of 4-alkyl-1-benzhydryl-2-(methoxymethyl)azetidin-3-ols by regio- and stereoselective alkylation of 1-benzhydryl-3-(N-alkyl)imino-2-(methoxymethyl)azetidine

The regio- and stereoselective alkylation at the position C-4 of 1-alkyl-2-substituted azetidin-3-ones was investigated. Imination of 1-benzhydryl-2-methoxymethylazetidin-3-one, followed by alkylation under kinetic conditions and final hydrolysis of the imino group, gave 4-alkyl-1-benzhydryl-2-methoxymethylazetidin-3-ones in which the susbstituents at C-2 and C-4 had the cis stereochemistry. The reduction of the carbonyl group afforded the corresponding 4-alkyl-1-benzhydryl-2-methoxymethylazetidin-3-ols. The structure and the stereochemistry of the azetidinols were confirmed by single crystal X-ray diffraction analysis.