Immobilization of (<scp>l</scp>)-valine and (<scp>l</scp>)-valinol on SBA-15 nanoporous silica and their application as chiral heterogeneous ligands in the Cu-catalyzed asymmetric allylic oxidation of alkenes
作者:Saadi Samadi、Akram Ashouri、Hersh I Rashid、Shiva Majidian、Mahsa Mahramasrar
DOI:10.1039/d1nj02580e
日期:——
functionalized by 3-chloropropyltrimethoxysilane. Next, by immobilization of chiral amino acid (S)-2-amino-3-methyl butanoic acid (L-valine) and chiral amino alcohol (S)-2-amino-3-methylbutane-1-ol (L-valinol), prepared via the reduction of L-valine by NaBH4/I2 in THF, on functionalized-SBA-15, chiral heterogeneous ligands AL*-i-Pr-SBA-15 and AA*-i-Pr-SBA-15 were prepared and characterized by FT-IR, XRD
以P123表面活性剂和原硅酸四乙氧基硅酸盐为原料,采用水热法合成SBA-15纳米多孔二氧化硅,然后用3-氯丙基三甲氧基硅烷进行功能化。接下来,通过固定手性氨基酸(S)-2-氨基-3-甲基丁酸(L-缬氨酸)和手性氨基醇(S)-2-氨基-3-甲基丁烷-1-醇(L-缬氨醇)通过在 THF 中通过 NaBH 4 /I 2还原L-缬氨酸制备,在功能化的 SBA-15 上,手性异质配体 AL*-i-Pr-SBA-15 和 AA*-i-Pr-SBA-15 是通过 FT-IR、XRD、TGA、EDX、SEM、BET-BJH 技术制备和表征。不对称烯丙基ic 烯烃的氧化是使用这些配体的铜配合物和合成的过酸酯完成的。通过改变各种参数如温度、溶剂、手性异质配体的量以及铜盐的类型和量来优化反应。在优化条件下,6 mg AL*-i-Pr-SBA-15 和 3.2 mol% Cu(CH 3 CN) 4 PF 6在 50