Controlled Activation of Dipicolinyl-Substituted Propargylic Alcohol by Ru(II) and Os(II) for Unprecedented Indolizine-Fused Metallafuran Complexes

Indolizine-fused metallafuran and metal–quinolizinium complexes were synthesized from reactions between dipicolinyl-substituted propargylic alcohol HCCC­(OH)­(CH2(2-py))2 and cis-[Ru/Os­(dppm)2Cl2] (dppm = 1,1-bis­(diphenylphosphino)­methane), revealing the operation of both non-vinylidene and vinylidene pathways regarding the Ru­(II)/Os­(II)–alkyne interactions. Strategies to control the selectivity of these two competitive pathways were successfully developed, paving ways to the rational design of Ru/Os-induced alkyne activations and metallacycles.