Sodium hydride → Acetic acid, 2-(1,4-dioxaspiro(4.5)dec-8-ylidene)-, ethyl ester

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Reaction Steps

To a suspension of NaH (60% mineral oil suspension, 33.3 g, 832.38 mmol) in anhydrous THF (1 L) was added a solution of 1,4-dioxaspiro[4.5]decan-8-one (100 g, 640.29 mmol) in anhydrous THF (500 mL) dropwise at 0° C. for 1 h and continued to stir for 1 h. Then triethyl phosphonoacetate (203.23 g, 832.38 mmol) was added to the above suspension dropwise at −20° C. in 1 h. The resulting mixture was allowed to warm to rt, stirred for 2 h, quenched with H2O (1 L) and extracted with EtOAC (1 L×3). The combined organic phases were washed with brine (1 L), dried over anhydrous Na2SO4, then filtered and concentrated in vacuo. The residue was purified by silica gel column chromatography (EtOAc/PE (v/v)=1/10) to give the title compound as pale yellow oil (157 g, 100%).

Provenance & Evidence