Synthesis of Tri-functional Bis-azide Photoaffinity Probe

Methyl 3-azidomethyl-5-azido-benzoate (1b) and its corresponding hydroxymethyl reduction product (1a) have been utilized for the synthesis of valuable nonradioactive photoaffinity probes. Previous preparations of (1a) depend upon a nonselective monoactivation of a bis-1,3-hydroxymethylaryl intermediate, leading to the expected statistical range of products/starting material. We report an alternate synthetic approach to these 1,3,5-trisubstituted molecules using recently described C-H activation and boronate refunctionalization methods.