Lifetime of the 1,4-biradical derived from alkyl phenylglyoxylate triplets: an estimation using the cyclopropylmethyl radical clock

摘要

There have been several studies on the mechanism and synthetic utility of the photoreactions of alkyl phenyl- glyoxylates since they were originally proposed to un- dergo Norrish Type II photoreactions by one of us (Scheme 1). No products resulting from cyclization of the intermediate 1,4-biradical have been observed, how- ever.