Fluorine-controlled C-H borylation of arenes catalyzed by a PSiN-pincer platinum complex.

An efficient, regioselective synthesis of fluorine-substituted arylboronic esters was achieved through fluorine-controlled C-H borylation of arenes with diboron catalyzed by a PSiN-platinum complex. The promising utility of the PSiN-platinum catalyst and its unique regioselectivity were demonstrated for the first time, which would complement the well-developed Ir-catalyzed C-H borylation.

Two reversible σ-bond metathesis pathways for boron-palladium bond formation: selective synthesis of isomeric five-coordinate borylpalladium complexes.

Two reversible σ-bond metathesis pathways for B-B bond activation to give borylpalladium complexes are demonstrated in the reaction of η(2)-(Si-H)Pd(0) complexes with B(2)pin(2). These two pathways are connected by fluxional behavior of the Si-H bond and can be efficiently controlled by the appropriate choice of phosphine ligand, enabling the selective synthesis of two types of five-coordinate borylpalladium complexes.

Efficient synthesis of diborylalkenes from alkenes and diboron by a new PSiP-pincer palladium-catalyzed dehydrogenative borylation.

The efficient synthesis of various diborylalkenes such as 1,1-, trans-1,2-, and cyclic 1,2-diborylalkenes from alkenes and diboron was achieved for the first time. Selective preparation of di- and monoborylalkenes was also realized by the appropriate choice of reaction conditions. The reaction was found to proceed via a new mechanism of dehydrogenative borylation through a monoborylpalladium complex bearing an anionic PSiP-pincer ligand as a key intermediate, which realized the efficient borylation without sacrificial hydroboration or hydrogenation of the alkene.

Synthesis of 4-arylcoumarins via Cu-catalyzed hydroarylation with arylboronic acids.

In the presence of 2-4 mol % of CuOAc, methyl phenylpropiolates having a MOM-protected hydroxy group at the ortho position underwent hydroarylation with various arylboronic acids in MeOH at ambient temperature, resulting in the formation of 4-arylcoumarins in high yields after the acidic workup. This method was effectively used for the synthesis of biologically active natural and artificial compounds.

Cu-catalyzed stereoselective conjugate addition of arylboronic acids to alkynoates.

The CuOAc-catalyzed reaction of internal alkynoates with arylboronic acids proceeded under mild conditions to yield trisubstituted cinnamates stereoselectively.