Chloromethyl ethyl ether → Methyl(1R,4S)-4-[(tert-Butoxycarbonyl)amino]-1-(ethoxymethyl)cyclopent-2-ene-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

To a 1.0 M solution of lithium hexamethyldisilazide in tetrahydrofuran (36.7 mL) was added a solution of methyl (1R,4S)-4-[(tert-butoxycarbonyl)amino]cyclopent-2-ene-1-carboxylate (4.00 g, 1.66 mmol) in tetrahydrofuran (6.0 mL) at −78° C. The resulting light brown solution was stirred at −78° C. for 30 min before (chloromethoxy)ethane (1.88 g, 19.9 mol) was added in one portion. The mixture was stirred at −78° C. for 1 h and then kept in a freezer reading at −25° C. overnight. The reaction was then quenched with saturated NH4Cl (50 mL). The organic layer was separated and the aqueous layer was extracted with CH2Cl2 three times. The combined organic layers were washed with brine, dried over Na2SO4, filtered, concentrated, and purified by flash chromatography (0 to 15% EtOAC in hexanes) to provide the desired product (3.29 g, 66%) as a cis/trans (3:2) mixture based on the analysis on reverse phase HPLC. MS calculated for C15H26NO5: (M+H) 300.2; found 200.2 (M+H-Boc).

Provenance & Evidence