Organopotassium for selective synthesis: Potassium-mediated anti-borylfunctionalization of alkynes

Organopotassium compounds, though known for over a century, have rarely been utilized for organic synthesis because of their unmanageably high reactivity. We report a reductive strategy for the generation of organopotassiums from alkynes to achieve uniquely anti -selective borylfunctionalization. The anti -diboration reaction with a bulky trialkoxyborane proceeds with broad substrate scope in a conventional flask to yield the synthetically useful building blocks ( E )-diborylalkenes. Flow microreactors offer precise control, enabling unsymmetrical installation of a boryl and another functional group in an anti -fashion to furnish high-value, multi-substituted alkenes with excellent regio- and stereoselectivity. Combined experimental and computational studies reveal that the potassium-induced anti -selectivity, which is opposite to the sodium-induced syn -selectivity, arises from the larger ionic radius of potassium. These findings establish a principle for stereochemical control using abundant alkali metal elements and provide efficient sustainable approaches to the synthesis of pharmaceuticals, agrochemicals, and functional materials.