Asymmetric β-Boration of α,β-Unsaturated N-Acyloxazolidinones by [2.2]Paracyclophane-Based Bifunctional Catalyst

An efficient copper-catalyzed asymmetric conjugate boration has been achieved by exploiting a new planar and central chiral bicyclic triazolium ligand. This protocol was highly efficient and gave a variety of chiral secondary alkylboronates in 97-99% ee. A preliminary mechanistic study supports the bifunctional nature of the catalyst.