Bis(chlorogermyliumylidene) and its significant role in elusive reductive cyclization

Abstract

Bis(chlorogermyliumylidene) 2 has been strategically obtained within redox-active bis(α-iminopyridine). Metal-free reduction of 2 followed by protonation led to elusive 2,3-di(pyridin-2-yl)piperazine with meso-stereoselectivity. Formation of persistent triplet diradicals upon reduction and isolation of piperazine stabilized Ge(II) dication intermediates provide convincing evidence for the crucial role of [GeCl]⁺ units in reductive cyclization.