Traceless Silicon-Tether Strategy for the Synthesis of a Tetraphenylammonium Salt

A traceless silicon-tether strategy enables the synthesis
of tetraphenylammonium
(Ph4N+) via intramolecular arylative quaternization.
The key cyclization step proceeded in 1.2% yield, a 12-fold improvement
over the intermolecular approach (0.1%). Subsequent two-step desilylation
furnished the target Ph4N+. DFT calculations
suggest β-silicon stabilization in the cyclization transition
state, although competing pathways are kinetically favored. This work
highlights the potential of intramolecular designs for accessing sterically
hindered organic cations.