Sodium Bicarbonate → tert-Butyl 1-(1-hydroxyprop-1-yl)-2-(tert-butyldimethylsilyloxy)-8-azaspiro[4.5]decane-8-carboxylate

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Reaction Steps

A solution of tert-butyl 1-formyl-2-(tert-butyldimethylsilyloxy)-8-azaspiro[4.5]decane-8-carboxylate (0.284 g, 0.714 mmol) from Step C in THF (7 mL) was cooled to −70° C. and ethyl magnesium bromide (3.0M, 0.262 mL, 0.786 mmol) was added. The reaction was stirred for 30 min and then an additional aliquot of ethyl magnesium bromide (3.0M, 0.050 mL, 0.142 mmol) was added. After 5 min, the reaction was diluted with ether, poured into sodium bicarbonate, and extracted three times with ether. The combined organic layers were washed with brine, dried over sodium sulfate, filtered, and concentrated. The residue was purified by flash chromatography eluting with 10 to 20% ethyl acetate in hexanes to afford the title compound (0.248 g) as a mixture of isomers. MS/EI (acetonitrile/water): m/z 354 (100%, M+1–74 (t-BuOH)), 372 (M+1–56 (C4H8); 428 (M+1); retention time=4.29 min.

Provenance & Evidence