RING CONTRACTION OF A 2-CARBON BRIDGED SPIROPENTANE

The diazoketone derived from tricyclo[4.1.0.0(1,3)]heptan-4-one on pho tolysis in dimethylamine leads to a novel product that appears to be f ormed via a cyclopropylcarbene rearrangement followed by dimethylamine addition and the cleavage of one of the cyclobutane rings. In a matri x at 15K, photolysis led to the loss of the 2085 cm(-1) diazo band and the formation of a new band at 2117 cm(-1) which is characteristic of a small ring ketene such as cyclopropylketene. Copyright (C) 1996 Els evier Science Ltd