Photodecarboxylative additions of α-keto carboxylates to phthalimides alkylation, acylation and ring expansion

The influence of the substitution pattern on reactivity and selectivity of the photodecarboxylative addition of α-keto carboxylates to N-methyl phthalimide was investigated. Secondary and tertiary α-keto carboxylates as well as glyoxylate gave alkylation and reduction products 2a-d, respectively. Pyruvate and the α-keto leucine anion both gave the ring expansion products 3e and 3f. In the latter case the acylation product 4e was additionally isolated