聚醚功能化离子液体辅助不对称氢化合成D-泛解酸内酯

Synthesis of D-(-)-pantolactone via asymmetric hydrogenation assisted by a polyether-functionalized ionic liquid

为了解决手性催化剂在不对称氢化中难以循环利用的问题,本研究基于氨基酸和咪唑鎓盐离子液体修饰的手性吡咯烷基双膦配体,采用聚醚胍盐离子液体辅助铑催化酮基泛解酸内酯均相不对称氢化合成D-泛解酸内酯。研究了铑催化剂前体、双膦配体结构、溶剂效应和聚醚离子液体掺杂对催化活性和对映选择性的影响。基于筛选出的最佳双膦配体,构建出“均相催化-液/固分离”体系用于手性催化剂的分离和循环。结果表明:该催化体系表现出较高的催化活性、对映选择性和长期稳定性,经过5次循环后未见催化性能有明显下降,为不对称氢化合成D-泛解酸内酯的可行性提供了理论和实验依据。

To solve the problem of recycling difficulty of chiral catalysts in asymmetric hydrogenation,rhodium-catalyzed homogeneous asymmetric hydrogenation of ketopantoyl lactone assisted by a polyether guanidinium ionic liquid was studied based on amino acid-and imidazolium-tagged chiral pyrrolidinodiphosphine ligands.The effects of rhodium precursor,diphosphine ligand structure,solvent effect and polyether ionic liquid doping on the catalytic activity and enantioselectivity were investigated.A homogeneous catalysis-liquid/solid separation system was constructed for the separation and recycling of the chiral catalyst using the optimal diphosphine ligand.The catalytic system showed high catalytic activity,enantioselectivity and long-term stability,and no significant decrease in catalytic performance was observed after 5 runs.This study provides the theoretical and experimental basis for the feasibility of asymmetric hydrogenation synthesis of D-pantolactone.