新型手性膦-硼烷配合物的合成及其在不对称催化氢化反应中的应用

以苯乙烯为原料,通过Sharpless不对称二羟基化反应合成高对映体纯的苯基乙二醇,经酯化、亲核取代反应转化为手性膦-硼烷配合物.后者克服了有机膦配体易氧化的缺点,其制备过程简单,易于提纯,在空气中可长期保存.该手性膦-硼烷配合物在四氟硼酸-甲醚的存在下解络,生成的自由膦不经分离直接与Rh(COD)Cl]₂作用生成手性膦-铑原位催化剂.在α-乙酰氨基肉桂酸甲酯的不对称氢化反应中,转化率为100%,对映选择性88%e.e.

Synthesis of New Chiral Diphosphine-borane Complex and Its Application to the Catalytic Asymmetric Hydrogenation

The high enantiomeric pure phenylglycol was synthesized from styrene by Sharpless asymmetric dihydroxylation. The diol was converted to chiral diphosphine-borane complex by esterification and nucleophilic substitution respectively. The complex was superior to free phosphine ligands which are sensitive to atmosphere. It's easy to prepare, purify and reserve. The complex was decomplexated in the presence of HBF₄·OMe₂ to yield quantitatively the free diphosphine which reacted directly with Rh(COD)Cl]₂ forming in situ catalyst. The asymmetric hydrogenation of methyl z-α-acetamidocinnamate has been accomplished in the presence of catalyst in 100% chemical conversion and 88% e.e..