Hydrochloric Acid → (1S,4S)-methyl 4-(tert-butoxycarbonylamino)-1-(2-(tert-butyldimethylsilyloxy)ethyl)cyclopent-2-enecarboxylate

Participants

Reaction Conditions

Reaction Steps

To a −70° C. solution of LiHMDS in THF (1M, 6.97 L, 6.97 mol) was added a solution of the product of Step B (763.5 g, 3.16 mol) in THF (800 mL) over a 2 h period while keeping the temperature at or below −68° C. The resulting solution was stirred for 45 min at −68° C. A solution of the product of Step C (1.267 kg, 4.426 mol) in THF (800 mL) was added over 1 h 50 min period while maintaining a temperature of ˜−66° C. The reaction was stirred at ˜-66° C. for 45 min. The reaction was warmed to −15° C. and worked up by addition to mixture of aqueous HCl and ice. The mixture was extracted with toluene, the organic layer was washed with water, brine and dried over MgSO4. The organic layer was concentrated and purified on silica gel using a mixture of EtOAc in heptanes to provide the product of Step D as a clear oil. 1H NMR (400 MHz, CHLOROFORM-d) d=5.69-5.86 (m, 2H), 4.79-4.93 (m, 1H), 4.68-4.80 (m, 1H), 3.67 (s, 3H), 3.53-3.62 (m, 2H), 2.16-2.30 (m, 1H), 2.04-2.16 (m, 2H), 1.70-1.81 (m, 1H), 1.41 (s, 9H), 0.78-0.91 (m, 13H), 0.00 (s, 6H).

Provenance & Evidence