Chemoselective Synthesis of 4,5‐Diarylpyrrolo[2,3‐ d ]pyrimidines (6,7‐Diaryl‐7‐deazapurines) by Consecutive Suzuki and Liebeskind–Srogl Cross‐Couplings

A new chemoselective synthesis of pyrrolo[2,3‐ d ]pyrimidines (7‐deazapurines) bearing two different aryl groups at positions 4 and 5 was developed based on two orthogonal cross‐couplings. Starting from 7‐benzyl‐protected 4‐(phenylsulfanyl)‐5‐iodopyrrolo[2,3‐ d ]pyrimidine, the Pd‐catalyzed Suzuki coupling with arylboronic acids proceeded selectively at position 5, followed by the Pd‐catalyzed Cu‐mediated Liebeskind–Srogl coupling at position 4. A small library of 4,5‐diaryl derivatives was prepared.