Transition metal-free regioselective cross-coupling of azine N-oxides with cymantrenyl lithium

The facile C-C coupling reaction of activated forms of azaaromatics (azine-N-oxides) with cymantrenyl lithium, as a nucleophile, has first been carried out. It has been established that aromatization of intermediate adducts can be realized through either oxidative or eliminative pathways, depending on the structure of the starting azine N-oxide. In particular, the dihydroazinyl intermediates, bearing the additional N(4)-atom relative to the N-oxide group, proved to undergo aromatization through the eliminative pathway. The X-ray studies of 3,6-diphenyl-1,2,4-triazine-5-yl-cymantrene have revealed that it is crystallized in both orthorhombic and monoclinic forms. (C) 2018 Elsevier B.V. All rights reserved.