Methyl morpholine oxide → tert-butyl 6-methyl-5-oxo-3,3a,4,5-tetrahydrocyclopenta[c]pyrrole-2(1H)-carboxylate

Participants

Reaction Steps

Dicobalt octacarbonyl (28.1 g, 82 mmol) was added to a solution of tert-butyl allyl(but-2-yn-1-yl)carbamate (16.4 g, 78 mmol) in dichloromethane (700 mL) at room temperature. The resulting mixture was and stirred under nitrogen for 1.5 h at room temperature, then cooled to 0° C. N-methylmorpholine-N-oxide (55.1 g, 470 mmol) was added in small portions over 1 h. The resultant mixture was stirred at 0° C. for 1 h, at ambient temperature for 2 h and filtered through a silica gel pad. The filter cake was washed with 1:1 mixture of ethyl acetate and hexanes until free of product. The filtrate was concentrated. Silica gel chromatography, eluting with 20-45% ethyl acetate in hexanes, gave tert-butyl 6-methyl-5-oxo-3,3a,4,5-tetrahydrocyclopenta[c]pyrrole-2(1H)-carboxylate (11.7 g, 63% yield). 1H NMR (400 MHz, chloroform-d) δ ppm 4.18 (2 H, d, J=16.29 Hz), 3.92-4.14 (1 H, m), 2.97-3.25 (1 H, m), 2.73-2.87 (1 H, m), 2.52-2.73 (1 H, m), 2.08-2.26 (1 H, m), 1.77 (3 H, s), 1.49 (9 H, s).

Provenance & Evidence