A novel Cu-catalyzed diastereo- and enantioselective desymmetrization of cyclopropenes to afford nonracemic cyclopropylboronates is described. Trapping the cyclopropylcopper intermediate with electrophilic amines allows for the synthesis of cyclopropylaminoboronic esters and demonstrates the potential of the approach for the synthesis of functionalized cyclopropanes.

No abstract

In this report, we establish that DM-Segphos copper(I) complexes are efficient catalysts for the enantioselective borylation of para-quinone methides. This method provides straightforward access to chiral monobenzylic and dibenzylic boronic esters, with enantiomeric ratios up to 96:4, using a commercially available chiral phosphine. Standard manipulations of the C–B bond afford a variety of chiral diaryl derivatives.

An efficient and general copper(i)-catalyzed silylation of p-quinone-methides is described. Non-symmetric dibenzylic silanes are obtained in high yields under mild reaction conditions. These compounds can be used as bench-stable benzylic carbanion precursors.

In this report, the enantioselective, copper-catalyzed borylation of β-amidoacrylates is disclosed. A broad variety of biologically important α-aminoboronates has been prepared with consistently high levels of enantiocontrol using an inexpensive copper catalyst and a commercially available chiral ligand. The method can be applied to the synthesis of novel boron-containing dipeptides and hemiboronates.