Functionalization of Mesoporous Silica Surface by Anchoring of Chemically-active Groups and Applications to Precise Organic Synthesis

成功制备了具有均匀孔隙结构的介孔二氧化硅（MS）。化学活性基团如氨基丙基、辛基和环氧环己基被锚定在MS表面，分别命名为MS- nh2、MS- c8和MS-ep。在骨架结构中还获得了包含乙烯链、氨基丙基、硫基和吡啶基团的介孔有机硅（分别简称为MOS-Ey、MOS-NH2、MOS-SH和MOS-Py）。利用这些样本进行了以下研究：乙醛在MS-NH2上的吸附：氨基丙基的锚定大大提高了乙醛的吸附率。特别是孔径缩小到约1 nm.2的MS-NH2在低浓度下的吸附率增加。表面稳定性及疏水/亲水性控制：MS-C8具有疏水特性。MS- ep表现出比MS更强的亲水性，吸水后孔隙结构保持稳定。MOS-Ey具有较强的疏水性，对烷烃蒸气具有较好的吸附性。MOS-SH氧化生成酸位：MOS-SH表面巯基经氧化处理转化为磺酸基（-SO_3H）。氨吸附微量热法表征的MOS-SO_3H固体酸度与铝硅酸盐沸石相当。在有机合成中的应用：我们发现不对称2,6-二（恶唑啉基）吡啶(pybox)/钌催化剂吸附在MS和MS- nh2等二氧化硅上，作为固体负载催化剂催化不对称环丙烷化反应。以重氮酯和烯烃的催化不对称环丙化反应为例，在水相和两相中均使用pybox/Ru（II）催化剂成功地进行了反应，得到了相应的环丙酯，对映选择性超过95%。此外，MOS-Py负载的单唑啉苯基(phemox)/钯配合物在333K下催化了碘硝基苯和乙苯衍生物的Sonogashira偶联反应，无需任何其他助催化剂如CuI。MOS-Py负载的phemox/Pd催化剂的效率与非负载的催化剂几乎相同。少

Mesoporous silicas(MS) with uniform pore structure were successfully prepared. Chemical active groups such as aminopropyl, octyl, and epoxycyclohexyl groups were anchored on MS surfaces, designated as MS-NH2,MS-C8 and MS-ep, respectively. Mesoporous organosilicas including ethytene chains, aminopropyl, thiol and pyridinium groups in the framework structures were also obtained (abbreviated as MOS-Ey,MOS-NH2,MOS-SH and MOS-Py, respectively). The following researches were performed by use of these samples.1.Acetaldehyde adsorption on MS-NH2 : The sorptivity of acetaldehyde was drastically improved by the anchoring of aminopropyl groups. Especially, the sorptivity at low concentration increased in MS-NH2 with narrower pore sizes of ca. 1 nm.2.Surface stability and hydrophobe/hydrophile control : MS-C8 exhibited hydrophobic character. MS-Ep showed more hydrophilic character than MS, while the pore structure stably retained after water sorption. MOS-Ey was rather hydrophobic and exhibited go … More od sorptivity for alkane vapor.3.Acid sites formation by oxidation of MOS-SH : Thiol groups on MOS-SH surface were converted to sulfonic acid ones (-SO_3H) by an oxidation treatment. Solid acidity of the MOS-SO_3H characterized by ammonia adsorption microcalorimetry was comparable to that of aluminosilicate zeolites.4.Application to organic synthesis : We found that asymmetric 2,6-bis(oxazolinyl)pyridine(pybox)/ruthenium catalyst was adsorbed on silica such as MS and MS-NH2 and acted as solid-supported catalyst for a catalytic asymmetric cyclopropanation reaction. In the case of catalytic asymmetric cyclopropanation reactions of diazoester and alkenes, the reaction was successfully proceeded with pybox/Ru(II) catalyst in both water phase and two phases to give the corresponding cyclopropylesters along with over 95% enantioselectivities. Furthermore, monooxazolinylphenyl (phemox)/palladium complexes supported on MOS-Py catalyzed Sonogashira coupling reactions of iodonitrobenzene and ethynybenzene derivatives at 333K without any other co-catalysts such as CuI. The efficiency of phemox/Pd catalyst supported on MOS-Py was almost same as the non-supported catalyst. Less