Sodium hydride → 1-(1,1-Dimethylethyl) 2-ethyl 4-(cyanomethylene)-1,2-piperidinedicarboxylate

Participants

Reaction Steps

To a suspension of 0.75 g (0.019 mol, 60% by weight in oil) of sodium hydride (washed three times with hexanes) in 40 ml of THF was added 3.34 g (0.019 mol) of diethylcyanomethylphosphonate. After stirring the reaction mixture for thirty minutes at room temperature, a solution of 4.26 g (0.016 mol) of ethyl 4-oxo-N-t-butoxycarbonyl-2-piperidinecarboxylate in 10 ml of THF was added. The mixture was stirred for 30 minutes at room temperature and 90 minutes at the reflux temperature of the reaction mixture, then cooled to room temperature and quenched with water. The organic layer was separated and the aqueous layer extracted twice with diethyl ether. The organic extracts were combined, dried over anhydrous magnesium sulfate, filtered and concentrated under vacuum. High pressure liquid chromatography of the residue afforded 3.58 g of ethyl 4-cyanomethylidene-N-t-butoxycarbonyl-2-piperidinecarboxylate.

Provenance & Evidence