Hydrogen atom transfer-induced selective borylation of C(sp3)-H bonds
As a highly atom-and step-economic strategy,the selective functionalization of C(sp3)-H bonds has been attracting considerable attention.Among them,borylation reactions,with their low toxicity and highly diverse transformative capabilities,have received lots of efforts from synthetic chemists.However,due to the inertness of C(sp3)-H bonds,controlling the chemo-and regioselectivity of C(sp3)-H borylation presents a significant challenge.As an emerging approach,achieving selective borylation of C(sp3)-H bonds through hydrogen atom transfer(HAT)offers unique advantages compared to conventional transition metal-catalyzed processes.In this review,we analyze various recent HAT-mediated methods for selective borylation of C(sp3)-H bonds.Categorizing them from the perspectives of intramolecular and intermolecular HAT,we emphasize the different sources of selectivity for each method and provide a detailed discussion of the involved mechanisms.Finally,we summarize the current limitations of the methods and provide outlooks for the future development in this field.
hydrogen atom transferC(sp3)-H borylationregioselectivityalkanephotocatalysis