Ethyl Acetate → 2-Cyclopropyl-6-hydroxy-4,4-dimethyl-1,2,3,4-tetrahydroisoquinoline

Participants

Reaction Conditions

Reaction Steps

A stirred, cooled (0° C.) solution of 6-hydroxy-4,4-dimethyl-1,2,3,4-tetrahydro-isoquinoline-2-carbaldehyde (Intermediate 20, 2.3 g, 11.2 1 mmol) in anhydrous tetrahydrofuran (40 mL) under argon was treated with titanium tetra-iso-propoxide (8.28 mL, 28 mmol) followed by 3M solution of ethyl magnesium bromide in diethyl ether (18.7 mL) and the reaction mixture was then heated at 55° C. overnight. It was then cooled in an ice-bath, quenched with saturated aqueous ammonium chloride solution and extracted with diethyl ether (×2). The combined organic phase was dried over anhydrous sodium sulfate, filtered and evaporated in vacuo to afford a yellow oily solid. Flash column chromatography over silica gel (230-400 mesh) using 10-20% ethyl acetate in hexane as the eluent afforded the title compound as a pale yellow solid (1.55 g, 63%).

Provenance & Evidence