Highly efficient and selective hydroboration of terminal and internal alkynes catalysed by a cobalt(ii) coordination polymer†
Hydroboration of terminal and internal alkynes has been carried out with extremely high efficiency by using a bench-stable and inexpensive cobalt(II) coordination polymer as a precatalyst in the presence of potassium tert-butoxide (KOtBu). Good to high yields of alkenylboronate esters were obtained in 5–30 min with low catalyst loading (0.025 mol%). Good chemoselectivity for alkyne vs alkene hydroboration was observed. A possible catalytic cycle involving the in situ formation of an active Co–H species is proposed based on additional experimental results. This work provides valuable implications for the design of efficient and practical base metal catalysts.