Photodecarboxylative additions of N-protected α-amino acids to N-methylphthalimide

Photoreactions involving N,N-dimethylated α-amino acid salts and N-methylphthalimide are dominated by photoreduction and acetone trapping. Only, N-phenyl glycinate underwent photodecarboxylative addition in a moderate yield of 30%. In contrast, N-acylated α-amino acid salts readily gave addition products in fair to high yields of 20–95%. Comparison experiments with N,N-dimethylacetamide and amino-/amido-containing phthalimides revealed the origin of the crucial electron-transfer step and the reactivity order NR3 » RCO 2 - ⩾ RCONR2 was established.