Unusual formation of 7-vinylcycloheptatriene derivatives in the catalytic cyclopropanation of cyclooctatetraene with diazocarbonyl compounds in the presence of rhodium catalysts
Yv. Tomilov et al., Unusual formation of 7-vinylcycloheptatriene derivatives in the catalytic cyclopropanation of cyclooctatetraene with diazocarbonyl compounds in the presence of rhodium catalysts, RUSS CHEM B, 48(11), 1999, pp. 2178-2180
The reaction of cyclooctatetraene with methyl diazoacetate or diazaacetone
in the presence of rhodium binuclear complexes gives, besides 9-substituted
bicyclo[6.1.0]nona-2,4,6-trienes (mixture of anti- and syn-isomers, total
yields 60-75%), isomeric beta-(cyclohepta-2,4,6-trien-1-yl)acrylates or 4-(
cyclohepta-2,4,6-trien-1-yl)but-3-en-2-one in 20-34% yields. In the case of
methyl diazoacetate, a mixture of E- and Z-isomers in a ratio of similar t
o 3.5 : 1 was obtained, while diazoacetone gave only E-isomer.