Filling the Gaps in the Challenging Asymmetric Hydroboration of 1,1-Disubstituted Alkenes with Simple Phosphite-Based Phosphinooxazoline Iridium Catalysts
作者:Marc Magre、Maria Biosca、Oscar Pàmies、Montserrat Diéguez
DOI:10.1002/cctc.201402822
日期:2015.1
ligands efficiently hydroborate a broader range of olefins than previous phosphinooxazoline ligands. In particular, a wide range of α‐tert‐butylstyrenes can be hydroborated that bear aryl substituents with different electronic and steric properties, which complements previous results with N‐heterocyclic copper catalysts, the only other system reported to date that has achieved these reactions.
我们已经确定了一种易于使用的基于膦恶唑啉的亚磷酸酯-恶唑啉催化体系,(S)-4-异丙基-2- 2-[(3,3',5,5'-四叔丁基-1,1' -联苯-2,2'-二基亚磷酸酯]苯基} -2-恶唑啉(L1 a),可以氢硼化一系列1,1-二取代芳基烯烃,具有高对映选择性(最高94%),优异的收率和完美的区域选择性。与以前的膦恶唑啉配体相比,新的亚磷酸酯-恶唑啉配体可高效硼氢化硼烯烃。特别地,大范围的α-叔可以将带有不同电子和空间特性的芳基取代基的丁基硼苯乙烯加氢硼化,这是对N-杂环铜催化剂的先前结果的补充,N-杂环铜催化剂是迄今为止报道的唯一实现这些反应的其他系统。