Accumulation of Active Species in Silica Mesopore: Effect of the Pore Size and Free Base Additives on Pd‐catalyzed Allylation using Allylic Alcohol,ChemCatChem

当前位置： X-MOL 学术 › ChemCatChem › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Accumulation of Active Species in Silica Mesopore: Effect of the Pore Size and Free Base Additives on Pd‐catalyzed Allylation using Allylic Alcohol
ChemCatChem ( IF 3.8 ) Pub Date : 2020-03-07 , DOI: 10.1002/cctc.202000266
Ken Motokura _{1,

2} , Sae Kawashima ₁ , Masayuki Nambo ₁ , Yuichi Manaka _{1,

3} , Wang‐Jae Chun ₄

Affiliation

A mesoporous silica‐supported Pd complex was prepared using various types of porous silica supports (pore size: 16–31 Å). The effects of the pore size and base additive properties on the catalytic allylation were investigated. The activity of the Pd‐catalyzed allylation of nucleophiles with specific base additives, such as 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU), is strongly affected by the mesopore size. The best allylation performance is obtained with a pore size of 23 Å. On the other hand, bases with smaller/larger molecular size and/or high nucleophilicity, such as K₂CO₃ and 1,4‐diazabicyclo[2.2.2]octane (DABCO), do not seem to show clear pore effect on the catalysis. The performance of the catalytic allylation significantly decreases by using such bases. Kinetic, spectroscopic, and control experiments reveal that the effective accumulation of Pd species and DBU in mesopores with appropriate pore sizes enhances their frequency factors.

中文翻译：

二氧化硅中孔中活性物种的积累：孔径和游离碱添加剂对使用烯丙醇的钯催化烯丙基化的影响

使用各种类型的多孔二氧化硅载体（孔径：16–31Å）制备了介孔二氧化硅负载的钯复合物。研究了孔径和基础添加剂性能对催化烯丙基化的影响。亲核试剂与特定的碱性添加剂（例如1,8-二氮杂双环[5.4.0]十一碳-7-烯（DBU））的Pd催化的烯丙基化活性受中孔大小的强烈影响。孔径为23Å时可获得最佳的烯丙基化性能。另一方面，具有较小/较大分子大小和/或高亲核性的碱基，例如K ₂ CO ₃和1,4-二氮杂双环[2.2.2]辛烷（DABCO），似乎对催化作用没有明显的孔效应。通过使用这种碱，催化烯丙基化的性能显着降低。动力学，光谱和控制实验表明，Pd和DBU在具有适当孔径的中孔中的有效积累增强了它们的频率因子。

更新日期：2020-03-07

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11