Synthetic Route to Rare Isoindolones Derivatives

International audienceA shorter and more versatile synthetic route has been developed to prepare tetrahydropyrido[2,1‐a]isoindolone and superior analogues. The key step of this synthesis is the formation of the lactam ring by a cyclization using Shibasaki's conditions.The isoindolone scaffold is present in many biologically active compounds. Here, we have developed a shorter and more efficient synthesis of tetrahydropyrido[2,1‐a]isoindolone. The key step of this approach is a cyclization to form the γ‐lactam ring under Shibasaki's conditions. Thus, tetrahydropyrido[2,1‐a]isoindolone and superior analogues, namely hexahydroazepino[2,1‐a]isoindolone and hexahydroazocino[2,1‐a]isoindolone, have been prepared in only three steps in 39, 25, and 19 % overall yields, respectively. This novel strategy offers a shorter alternative to existing procedures