Sodium hydride → Diethyl vinylphosphonate

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A sample of 60% NaH in mineral oil (32 mmol) was placed in a 2-neck round bottom flask and charged with dry hexane (20 mL). This solution was allowed to stir for ten minutes, after which the hexane-mineral oil layer was completely removed. The flask was then charged with dry tetrahydrofuran (100 mL), followed by dropwise addition of 1,2-HS(C6H4)SH (14 mmol) with constant stirring. The resulting solution was cooled at 0° C. and BrCH2CH2P(O)(OC2H5)2 (30 mmol) was added dropwise with constant stirring over a period of 30 minutes. Excess NaH was quenched by addition of 50 mL of deionized water. The solution was extracted from the ethyl acetate (3×50 mL) and washed with a saturated sodium chloride solution. The organic layer was dried over anhydrous sodium sulfate. Upon filtering, the solvent was removed in vacuo to afford 6 in 94% yield along with a trace amount of diethyl vinylphosphonate. The compounds were separated on a silica gel column (20 cm; 60 mesh) using 90:10 ethyl acetate to hexane solvent mixture. Removal of the solvent in vacuo, afforded compound 6 as a viscous, yellow-green oil with an overall yield of 91%. High resolution FAB/MS Anal. Calcd. for C18H32O6P2S2 : 470.1115; Found: [M+H+ ], m/z=471.1119. 1H NMR (CDCl3): δ 1.27 (t, 3JHH =9.0 Hz, 12H, OCH2CH3), 2.02 (m, 4H, PCH2CH2), 3.06 (m, 4H, PCH2CH2), 4.05 (m, 8H, OCH2CH3), 7.2 (m, 4H, C6H4). 13C NMR (CDCl3): δ 16.3 (d, 3JPC =6.0 Hz, OCH2CH3), 25.8 (d, 1JPC =136 Hz, PCH2CH2), 26.2 (s, PCH2CH2), 61.7 (d, 2JPC =6.0 Hz, OCH2CH3). 31P NMR (CDCl3): δ29.4 (s).

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