Triethylamine → [3,3-dimethyl-1(S)-(4-methyl-2,6,7-trioxabicyclo[2.2.2]oct-1-yl)butyl]carbamic acid benzyl ester

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Reaction Steps

To a solution of 2(S)-benzyloxycarbonylamino-4,4-dimethylpentanoic acid 3-methyl-oxetan-3-ylmethyl ester (21.5 g, 59 mmol) in dry DCM (50 ml) was added BF3.Et2O (0.4 ml, 3.2 mmol). After 5 h, triethylamine (0.9 ml, 6.4 mmol) was added and stirring was continued for 30 min at room temperature. The solvent was evaporated using a rotavap and the resulting oil was redissolved in ethyl acetate and was washed with 50 ml of 3% NH4Cl solution followed by brine. The ethyl acetate layer was dried over MgSO4, the solvent was evaporated and the residue was purified with column chromatography using silica gel and 20:80 EtOAc:Hexane as eluent to give [3,3-dimethyl-1(S)-(4-methyl-2,6,7-trioxabicyclo[2.2.2]oct-1-yl)butyl]carbamic acid benzyl ester (15.5 g).

Provenance & Evidence