Highly Efficient Asymmetric Michael Addition of Diaryl Phosphine Oxides to α,β-Unsaturated N-Acylated Oxazolidin-2-ones
作者:Depeng Zhao、Linqing Wang、Dongxu Yang、Yixin Zhang、Rui Wang
DOI:10.1002/asia.201200025
日期:2012.5
A highlyefficientasymmetricMichael reaction of diarylphosphineoxides with α,β‐unsaturated N‐acylated oxazolidinones has been developed. Excellent enantioselectivities (up to >99 % ee) and chemical yields (up to 99 %) were achieved with a broad substrate scope of the oxazolidinones. The bidentate property of oxazolidinones was found to be critical for high enantioselectivities.
Asymmetric β-Boration of α,β-Unsaturated <i>N</i>-Acyloxazolidinones by [2.2]Paracyclophane-Based Bifunctional Catalyst
作者:Lei Zhao、Yudao Ma、Wenzeng Duan、Fuyan He、Jianqiang Chen、Chun Song
DOI:10.1021/ol302839d
日期:2012.11.16
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.