Synthesis of a sensitive and selective potassium-sensing fluoroionophore.

An efficient synthesis is reported that delivers in 5 steps and 52% overall yield a new structurally simplified fluorescent K(+) sensor with improved K(+) sensitivity and selectivity over existing K(+) sensors. The synthesis procedure utilizes a new template-directed oxidative C-N bond-forming macrocyclization reaction and reports new approaches to Pd(0), Sandmeyer-like and metal-free aminoarylations, as well as organotitanium additions to vinylogous sulfonates.