Triphenylsilane-fused Porphyrins

A reaction sequence of 2-(diphenylsilyl)phenylation by Negishi coupling and intramolecular sila-Friedel-Crafts reaction has been explored for the synthesis of monotriphenylsilane-fused porphyrins 5M and 6M (M= Ni, Zn) and bis-triphenylsilane-fused porphyrins 7M and 8Ni. A triply linked triphenylsilane-fused NiII porphyrin, 13Ni, was synthesized in a stepwise manner involving the above reaction sequence and a final Pd-catalyzed C-H activating arylative cyclization. The silicon atom in 13 Ni takes a distorted planarized structure with an almost perpendicular Si-phenyl group, causing an electronic effect due to effective sigma*-pi* interaction.