Direct Boronylation by Transition Metal-catalyzed Aromatic C-H Functionalization

4 Direct Boronylation by Transition Metal-catalyzed Aromatic C-H Functionalization 

In terms of atom-economy a very attractive strategy for accessing arylboronic acids is the direct boronylation of arenes through a transition metal promoted C-H functionalization. In addition to the catalyst, a suitable boron donor is required, and both diboronyl esters and dialkoxyboranes are very appropriate in this role. The concept of this type of direct borylation was first demonstrated on alkanes using photochemical 

Harrity and co-workers described the application of 2-substituted 1-alkynylboronic esters in the Dotz cycloaddition of Fisher chromium carbene complexes, affording in a highly regioselective fashion a novel class of hydroxy-naphthyl boron pinacolates (entry 18, Table 1.3) [217]. These reaction products also provided, upon treatment with ceric ammonium nitrate, the corresponding quinone boronic esters. 

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