ELECTRON-TRANSFER PHOTOCHEMISTRY OF QUADRICYCLANONE - STEREOSPECIFIC NUCLEOPHILIC CAPTURE OF A RADICAL-CATION AND SINGULAR REARRANGEMENT

The electron transfer photo-sensitized reaction of quadricyclanone (1) with methanol produces a single product, 7-syn-methoxybicyclo[2.2.1]h ept-5-en-2-one (2) via nucleophilic attack of methanol on the radical cation of 1. The structure of the product and the stereochemistry of t he methoxy group reveal that the radical cation is captured by backsid e attack of methanol on one cyclopropane function followed by a specif ic cyclopropylcarbinyl to butenyl rearrangement.