Synthesis of Macrocycles by Cyclocarbonylation with Palladium Dendrimers

Significance

The first intramolecular cyclocarbonylation reaction with recyclable Pd-complexed dendrimers on silica gel was developed to form oxygen-, nitrogen-, or sulfur-containing large ring-fused heterocycles. Thus, the reaction of 1 with G1-Pd (0.15 mol% Pd) was performed in the presence of DIPEA in toluene under 100 psi CO atmosphere to give macrocyclic compounds 2 in 70-92% yield (12-18 membered rings; 27 examples). The catalyst was reused seven times without loss of catalytic activity.