Synthesis of N ‐Heterocycles‐Fused Azasilines by Palladium‐Catalyzed Si‐Si Bond Activation
Résumé
Azasilines fused nitrogen heterocycles are prepared in excellent yields (from 74 to 98 % according to the structures) for the first time in one operation with high regio‐ and stereoselectivities. The key step consists of an intramolecular palladium‐catalyzed cyclisation reaction of heteroaryl disilane cores, bearing double or triple bond. We first studied the reactivity of pyridyl heterocycles, using xylenes as solvent and Pd(dba)2‐P(OEt)3 as catalyst at 130 °C. The Z configuration of the adducts suggested that the reaction proceeds following a syn addition on the alkyne. This strategy has then been illustrated by the synthesis of complex polyheterocyclic scaffolds (phenothiazine, indole, carbazole, quinoline and tetrahydroquinoline) starting from other nitrogen heteroaryl compounds, to demonstrate the potential of the process, in order to obtain promising biological scaffolds.