Reaction of 1-Acetyl-1-(diazoacetyl)cyclopropane (11) with 2-Cyclo-hexen-1-one. A solution containing 513 mg (3.4 mmol) of alpha-diazo ketone 11 and 1.62 g (16.9 mmol) of 2-cyclohexen-1-one in 25 ml CH2Cl2 was treated with 2 mg of rhodium(II) octanoate. The reaction was complete after 4 h. The crude oil was purified to give 303 mg (41%) of 4,10-dioxo-5,12-epoxy-12-methyl- spiro[2.3.4]non-ane (19) as a white crystalline solid; mp 95-96^oC; IR (CCl4) 1750, 1687, 1453, 1333, and 993 cm^-1; ¹H-NMR (300 MHz, CDCl3) δ 0.77 (m, 1H), 1.04 (m, 1H), 1.14 (m, 4H), 1.32 (m, 1H), 1.70 (m, 1H), 1.84 (m, 1H), 1.92 (m,1H), 2.20 (m, 1H), 2.30 (m, 2H), 2.70 (m, 2H), and 4.33 (s, 1H); ¹³C-NMR (75 MHz, CDCl3) δ 12.1, 14.7, 15.2, 20.1, 27.0, 39.9, 40.3, 40.6, 57.6, 86.2, 88.1, 210.7, and 211.5; Anal. Calcd. for C13H16O3: C, 70.87; H, 7.33. Found: C, 70.92; H, 7.34.