Biohydroxylations of Cbz-protected alkyl substituted piperidines by Beauveria bassiana ATCC 7159

N-Benzyloxycarbonyl (Cbz) protected piperidines are hydroxylated with greater regioselectivity than the corresponding N-benzoyl analogues when incubated with the fungus Beauveria bassiana ATCC 7159. Cbz-protected piperidines 1–3, 5–7, have been biotransformed by growing cell suspensions of this fungus to yield predominantly 4-hydroxylated products in up to 48% yield. The regiospecificity of hydroxylation was only compromised significantly with N-Cbz-3-methylpiperidine 3 and N-Cbz-2-methylpiperidine 4 where hydroxylation occurred in both the 3 and 4 positions.