GAS-PHASE ADDITION OF [C-13]METHYLENE TO ETHENE - REARRANGEMENT OF CHEMICALLY EXCITED PROPENE

Reaction of ethene with singlet [C-13]methylene, generated photochemic ally from [C-13]diazomethane at four pressures in the range 35-800 Tor r, reveals rearrangement of excited [3-C-13]propene (3), the product o f insertion, to [1-C-13]propene (1) and [2-C-13]propene (2). This prev iously unrecognized reaction is formulated as the reverse of the therm al rearrangement of cyclopropane to propene, well known in both therma l and chemically excited modes. The origin of a small excess of 1 over 2 is discussed. Mercury sensitization does not alter the observations at 820 Ton.