This lecture intends to showcase unorthodox ways of harnessing the reactivity of alkynes via highly selective metal-catalyzed transformations, including trans-hydrogenation, trans-hydroboration, trans- hydrostannation, and trans-hydro(chloro)alkynylation, which have little precedent in the literature, if any.

Even more perplexing is the ability to transfer both H-atoms of H2 to one and the same C-atom of a triple bond with concomitant formation of a discrete metal carbene at the adjacent position (“gem- hydrogenation”). This entirely new reactivity mode unlocks numerous opportunities for organic synthesis and organometallic chemistry alike, which we have started to explore.

The underlying mechanisms will be discussed in some detail; selected applications to target-oriented synthesis are meant to showcase the current state of development.

A. Fürstner, J. Am. Chem. Soc. 2019, 141, 11.