一种可回收和重复使用配体的合成及其在AD反应中的应用

Sythesis of a Kind of Recoverable and Reusable Ligand and Its Application in AD Reaction

以 3 ,6-二氯哒嗪为桥联基与奎宁及二氢奎宁在 Na H和 DMF中反应 ,生成物奎宁一侧在 AIBN存在下与巯基乙醇反应 ,进而氧化成砜 .生成的金鸡纳生物碱衍生物新配体 1在 AD反应中对 6种烯烃的二羟化反应表现了很高的对映选择性 ( 88%～ 99% e.e.)和化学产率 ( 74%～ 91 % ) .配体 1可以回收和重复使用 ,在以肉桂酸乙酯为底物的 AD反应中 ,重复使用 4次 ,其催化活性和对映选择性保持不变 .

Dichoropyridazine was reacted with quinidyl and dihydroquinidyl in the presence of NaH in DMF to give compound 2. The side of quinidyl was reacted with 2-mercaptoethanol, then was oxidized to give ligand 1. Ligand 1 delivers excellent enantioselectivity as well as specific chemoselectivity in the asymmetric dihydroxylation(AD) of six olefins(88%—99% e.e). and 74%—91% isolated yields were obtained in AD reaction. Furthermore this ligand can be recovered and reused. Its enantioselectivity and chemoselectivity were unchangeable when it was reused for four times in AD reaction with cinnamic ethyl as the substrate.