To an Ar filled flask containing 5 g (4.33 mmol) of tetrakis(triphenylphosphine) palladium (Aldrich) and 15.92 g (50.96 mmol) of trans-4-t-butoxycarbonylaminocyclohexyl-(allyloxycarbonyl)methylamine was added 220 mL of dry THF. After the solids had dissolved, the solution was stirred for 5 min. and 50 mL (483 mmol) of diethylamine (Aldrich) was added in one portion. The solution was stirred at ambient temperature overnight. The solvents were removed by rotovap, and the residue partitioned between ice-cold 0.5M aq HCl and ethyl acetate. The organic layer was extracted with cold 0.5M aq HCl, and the combined aqueous layers washed with ethyl acetate, basified with aq NaOH and extracted with 3 x ethyl acetate. The combined organic layers were washed with water, brine, dried over Na2SO4 and solvents removed to give an oil that was chromatographed on 250 g of fine SiO2 using 90:10:1 chloroform-methanol-ammonium hydroxide to give 7.9 g (56%) of the title compound as a colorless semi-solid: NMR (CDCl3) d 0.5-1.5 (m, 4H), 1.8-1.3 (m, 1H), 1.44 (s, 9H), 1.81 (dm, J=10.3, 2H), 2.03 (din, J=10.3, 2H), 2.53 (d, J=6.6, 2H), 3.37 (br s, 1H), 4.44 (br s, 1H).
