Mc. Pirrung et al., DIPOLAR CYCLOADDITION OF CYCLIC RHODIUM CARBENOIDS TO DIGONAL CARBON - SYNTHESIS OF ISOEUPARIN, Tetrahedron letters, 35(34), 1994, pp. 6229-6230
Diazocyclohexanediones undergo dipolar cycloadditions with substituted
acetylenes to provide 2-substituted tetrahydrobenzofuran-4-ones and w
ith allenes to provide 2(H)-3-methylenedihydrofuranones.