An efficient synthesis of carbazole-based secretory phospholipase A2 (sPLA2) inhibitors LSN433771 and LSN426891

The flexible and efficient synthesis of two structurally similar carbazole derivatives is described. This general strategy features an intramolecular palladium-mediated biaryl coupling reaction to join two aromatic domains of the target molecules. Formation of the carbazole core is accomplished via nitrene insertion. The synthesis of secretory phospholipase A₂ (sPLA₂) inhibitors LSN433771 (1) and LSN426891 (2) is detailed.