Boron trifluoride etherate → 1-Ethyl-1,3,4,9-tetrahydro-6-(phenylmethoxy)pyrano[3,4-b]indole-1-acetic acid methyl ester

Participants

Reaction Steps

A mixture consisting of 5-benzyloxytryptophol (24.0 g, 0.090 mol), methylene chloride (600 mL), methyl 3-methoxy-2-pentenoate (16.8 g, 0.177 mol) and borontrifluoride etherate (2 mL) is stirred at room temperature for 3 hours. The reaction mixture is washed with 5% NaHCO3 (2×200 mL), water (2×200 mL) and once with brine (200 mL), dried (MgSO4), filtered and concentrated to give 38.0 g crude product. The crude product is flash chromatographed on silica gel using 20% ethyl acetate/hexane as an eluent to afford 29.0 g pure title compound, m.p. 98°-100° C.

Provenance & Evidence