Dimethylformamide → 1,1-Dimethylethyl 1-[2-(butyloxy)-2-oxoethyl]-6-cyano-5-methyl-3,4-dihydro-2(1H)-isoquinolinecarboxylate

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Reaction Conditions

Reaction Steps

A solution of 1,1-dimethylethyl 1-[2-(butyloxy)-2-oxoethyl]-5-methyl-6-{[(trifluoromethyl)sulfonyl]oxy}-3,4-dihydro-2(1H)-isoquinolinecarboxylate (Preparation 17; 837 mg, 1.64 mmol) in N,N-dimethylformamide (6 ml) was degassed under vacuum for 15 min. Tetrakis(triphenylphosphine)palladium(0) (190 mg, 0.164 mmol) and zinc cyanide (251 mg, 2.13 mmol) were then added and the resulting orange mixture stirred at 100° C. for 4 h. The mixture was cooled to room temperature and insoluble material filtered off and washed with ethyl acetate. The mother liquors were concentrated in vacuo and the residue dissolved in ethyl acetate. The solution was washed with saturated sodium bicarbonate and the aqueous phase further extracted twice with ethyl acetate. The combined organic phases were washed with brine, dried over MgSO4 and concentrated in vacuo. Purification by flash chromatography on silica gel, eluting with 5-25% ethyl acetate in cyclohexane, gave the title compound (600 mg) as a colourless oil.

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