Sodium hydride → Dimethyl (1-bromo-2-oxoheptyl)phosphonate

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Reaction Steps

A solution of 0.31 ml of dimethyl-(2-oxo-heptyl)phosphonate in 4 ml of benzene was added dropwise to a suspension of 43 mg of 80% sodium hydride in 5 ml of dry benzene until there was no more evolution of hydrogen. An hour afterwards, 0.255 g of N-bromosuccinimide was added and the mixture stirred for 15 minutes, giving the carbanion of dimethyl-(1-bromo-2-oxo-heptyl)-phosphonate. The aldehyde was then added and stirring continued for another 15 minutes. The organic phase was washed with water, a 5% aqueous solution of NaH2PO4, and again with water until the washing were neutral, and the organic phase was evaporated to dryness. The residue, 0.6 g, was chromatographed on 20 g of silica gel to give 0.335 g of dl-5β-(2'-bromo-3'-oxo-oct-1'-trans-1'-enyl)-2α,4α-dihydroxycyclopentane-1α-acetic acid-γ-lactone-4-acetate, m.p. 121°-123° C.; λmaxMeOH 241 mμε= 11,700 (72% yield), by elution with benzene-ethyl ether (90:10 ).

Provenance & Evidence