4-Hydroxybenzaldehyde → (2S,4R,5R)-2-benzhydryl-5-(4-hydroxy-benzylamino)-tetrahydropyran-4-ol

Participants

Reaction Conditions

Reaction Steps

To a solution of (2S, 4R, 5R)-5-amino-2-benzhydryl-tetrahydro-pyran-4-ol 31a (0.02 g, 0.09 mmol), 4-hydroxybenzaldehyde (0.01 g, 0.09 mmol) and glacial acetic acid (0.005 g, 0.09 mmol) in 1,2-dichloroethane (5 ml) was added portionwise NaCNBH3 (0.007 g, 0.11 mmol) in methanol (1 ml). The reaction was continued for 4 hr. Water was added to quench the reaction and the mixture was stirred for 30 minutes at 0° C. The reaction mixture was stirred with saturated aqueous NaHCO3 and the product was extracted with methylene chloride (3×10 ml). The combined organic phases were washed with brine, water and dried over anhydrous Na2SO4. Solvent was removed under reduced pressure, and the residue was purified by flash chromatography (Hexane/Ethyl Acetate/Triethylamine 3:2:0.2) to give (2S, 4R, 5R)-2-benzhydryl-5-(4-hydroxy-benzylamino)-tetrahydropyran-4-ol, (−)-32a, 0.03 g (80%, [α]D=(−)72.6, c=1, MeOH).

Provenance & Evidence