(1,8-Diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)-acetaldehyde → 1-(1,8-Diethyl-1,3,4,9-tetrahydropyrano[3,4-b]indol-1-yl)-propan-2-ol

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Reaction Steps

A solution of compound 8 (275 mg, 1.01 mmol) in dry THF (4 mL) was added dropwise over five minutes to a stirred solution of 1M MeMgCl in THF (1.52 mL, 1.52 mmol, 1.5 eq) at 0° C. under argon and allowed to warm slowly to room temperature. After stirring for two hours, another equivalent of 3M MeMgCl in THF (337 μL, 1.01 mmol, 1.0 eq) was added, and the mixture was stirred for an additional hour. The mixture was then diluted with saturated NaHCO3 and extracted three times with EtOAc. The combined organic phases were dried with Na2SO4, concentrated, and purified by column chromatography using 20:80:EtOAc:Hexane to give a yellow solid (280 mg, 96%): mp 103-104° C. 1HNMR (CDCl3, δ TMS) shows a 2:1 mixture of diastereomers. MS−: m/z 322 (MCl−), 286 ([M−H]−). Anal. (C18H25NO2): C, H, N. The product was carried on to the next step as a mixture of diastereomers.

Provenance & Evidence