Under N2, an ice-cooled flask containing THF (100 mL) was charged with sodium hydride (5.7 g, 142.5 mmol) to which ethyl 2-(diethoxyphosphoryl)acetate (32 g, 142 mmol) was added. The ice bath was removed and a solution of intermediate 7 (21.8 g, 56.7 mmol) in THF (120 mL) was slowly added to the preformed anion. The reaction was heated to reflux overnight. The reaction mixture was cooled to rt and partitioned between EtOAc and water. The organic layer was separated and the aqueous layer was extracted with EtOAc. The combined organic layers were washed with brine, dried over anhydrous Na2SO4 and concentrated in vacuo to give ethyl 3-(6-(4-(benzyloxy)butoxy)-2-pivalamidopyridin-3-yl)acrylate (intermediate 8) (13.3 g, 52%) as a white solid. mp: 75-76° C.
