[C:1]([N:9]1[CH2:14][CH2:13][CH:12]([C:15](OCC)=[O:16])[CH2:11][CH2:10]1)(=[O:8])[C:2]1[CH:7]=[CH:6][CH:5]=[CH:4][CH:3]=1.B([O-])([O-])[O-].[Li+].[Li+].[Li+].B(OC)(OC)OC.O>C1COCC1>[C:1]([N:9]1[CH2:14][CH2:13][CH:12]([CH2:15][OH:16])[CH2:11][CH2:10]1)(=[O:8])[C:2]1[CH:3]=[CH:4][CH:5]=[CH:6][CH:7]=1
10.4 g (0.04 mol) of ethyl 1-benzoyl-4-piperidine-carboxylate were dissolved in 90 ml of THF and treated with a solution of 0.871 g (0.04 mol) of lithium borate in 20 ml of THF. 0.45 ml (0.004 mol) of trimethyl borate was added and the mixture was stirred at room temperature for 60 hrs. The reaction mixture was treated with water and stirred for 1.5 hrs. The mixture was extracted with ethyl acetate and the organic phase was washed with water and saturated sodium chloride solution and dried over sodium sulfate. The residue was chromatographed on silica gel with ethyl acetate/hexane (1:1). 7.8 g (90%) of 1-benzoyl-4-hydroxymethyl-piperidine were obtained as white crystals; m.p. 84°-87°.
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