Synthesis and transformations of 2-(phenylhydroxymethyl)cyclohexylamines

Diastereomeric 2-(phenylhydroxymethyl)cyclohexylamines were synthesised by reduction of 2-benzoylcyclohexylamines. (1S∗,2R∗)-2-Benzoylcyclohexylamine can be reduced diastereoselectively to the corresponding γ-amino alcohol with sodium borohydride; for the trans counterpart (1R∗,2R∗)-2-benzoylcyclohexylamine, lithium aluminium hydride was found to be a selective reducing agent. In both cases, high syn selectivities were observed. The amino alcohols were transformed to the corresponding cyclohexane-fused tetrahydro-1,3-oxazin-2-ones and -2-thiones. The γ-amino alcohols reacted with arylimidates to afford 4,5-dihydro-6H-1,3-oxazines. Their cyclization with phenyl isothiocyanate yielded 2-phenyliminotetrahydro-1,3-oxazines.