Synthesis of isogranulatimides A and B analogues possessing a 7-azaindole unit instead of an indole moiety

The synthesis of a new family of isogranulatimides analogues is described in which a 7-azaindole replaces the indole moiety. The key step is the photocyclization of the aza didemnimide intermediates which leads to two isomeric analogues of isogranulatimides A and B. A derivative bearing a carbohydrate part linked to the azaindole via a β-N-glycosidic bond was also prepared.