Sodium hydride → Ethyl 2-(cyclopropylmethyl)-1,3-dithiane-2-carboxylate

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Reaction Steps

A solution of bromomethylcyclopropane (19.5 g, 0.144 mol) and 2-carboethoxy 1,3-dithiane (25.0 g, 0.130 mol) in dry N,N-dimethylformamide (55 mL) was added drop wise over 20 minutes to an ice cooled suspension of sodium hydride (60% oil dispersion, 6.24 g, 0.156 mol, 1.2 eq; pre-washed twice with n-pentane) in benzene (165 mL). The suspension was stirred at room temperature for 18 hours and then poured into 15% aqueous ammonium chloride. The mixture was extracted with methyl tert-butyl ether and the organic phase was separated, washed with water and then brine, dried over magnesium sulfate and filtered. The solvent was evaporated from the filtrate to give ethyl 2-(cyclopropylmethyl)-1,3-dithiane-2-carboxylate (31.2 g, 97.4%) as a light brown oil. 1H-NMR (400 MHz, CDCl3): δ=0.07-0.15 (m, 2H), 0.37-0.47 (m, 2H), 0.76-0.89 (s, 1H), 1.25 (t, J=8 Hz, 3H), 1.70-1.85 (m, 1H), 1.88 (d, J=8 Hz, 2H), 2.01-2.13 (m, 1H), 2.54-2.65 (m, 2H), 3.13-3.26 (m, 2H), 4.19 (q, J=8 Hz, 2H).

Provenance & Evidence