The first planar chiral ferrocenylborenium species (pR)-3+ is obtained in the enantiopure form by halide abstraction from the corresponding chloroborane adduct (pR)-2 using Krossing's salt. Competition experiments suggest that the Lewis acidity of (pR)-3+ is higher than that of B(C6F5)3 towards anions and slightly lower towards neutral Lewis bases. The ferrocenylborenium species (pR)-3+ is examined as a catalyst for the stereoselective hydrosilylation of ketones.
第一种平面手性
铁酰基
硼阳离子(pR)-3+是通过使用Krossing的盐从相应的
氯硼烷加合物(pR)-2中抽取卤素而以对映体纯净的形式获得的。竞争实验表明,(pR)-3+的
路易斯酸性对阴离子的强度高于B(
C6F5)3,而对中性路易斯碱的强度则稍低。
铁酰基
硼阳离子(pR)-3+作为催化剂被研究用于酮的立体选择性氢
硅化反应。