Abstract:
A library of bidentate diols, as well as tridentate triols and aminodiols, derived from
(+)-sabinol, was synthesized in a stereoselective manner. Sabinol was transformed into allylic
trichloroacetamide via Overman rearrangement of the corresponding trichloroacetimidate. After
changing the protecting group to Boc, the enamine was subjected to stereospecific dihydroxylation
with OsO4/NMO, resulting in the (1R,2R,3R,5R)-aminodiol diastereomer. The obtained primary
aminodiol was transformed to a secondary analogue. The ring closure of the N-benzyl-substituted
aminodiol with formaldehyde was investigated and regioselective formation of the spiro-oxazolidine
ring was observed. Hydroboration or dihydroxylation of sabinol or its benzyl ether with OsO4/NMO
resulted in the formation of sabinane-based diols and triols following a highly stereospecific reaction.
Treatment of sabinol with m-CPBA afforded O-benzoyl triol as a diastereoisomer of the directly
dihydroxylated product, instead of the expected epoxy alcohol. The resulting aminodiols, diol, and
triols were applied as chiral catalysts in the reaction of diethylzinc and benzaldehyde from moderate
to good selectivity.
