Use of a radical clock to study the photodecarboxylation of amino acidatocobalt(III) complexes†

Abstract

The products of steady state UV irradiation of amino acidatobis(2,2′-bipyridine)cobalt(III) complexes have been identified. The products of these photodecarboxylation reactions include a carbonyl compound derived from the amino acid side chain. The viability of an aminocyclopropylmethyl radical clock as a potential mechanistic probe for the reaction was assessed by ab initio methods. The required cyclopropylglycine containing substrate was synthesized and used to show that reaction of an α-carbon centred radical must be a fast step if it occurs in the reaction sequence leading to formation of the intermediate metallacyclic complexes.