Zirconium(IV) Chloride as a New, Highly Efficient, and Reusable Catalyst for Acetylation of Phenols, Thiols, Amines, and Alcohols under Solvent-Free Conditions
作者:Asit K. Chakraborti、Rajesh Gulhane
DOI:10.1055/s-2004-815442
日期:——
chloride has been found to be a new. highly efficient, and reusable catalyst for acetylation of structurally diverse phenols, thiols, amines and alcoholsundersolvent-free condtions. Acetylation of sterically hindered and electron deficient phenols is achieved in excellent yields with stoichiometric amounts of Ac 2 O at room temperature. Acid-sensitive alcohols undergo acetylation with excellent chemoselectivity
已发现氯化锆 (IV) 是一种新的。一种高效、可重复使用的催化剂,用于在无溶剂条件下对结构不同的酚、硫醇、胺和醇进行乙酰化。在室温下使用化学计量量的 Ac 2 O 以极好的收率实现空间位阻和缺电子酚的乙酰化。酸敏感醇以优异的化学选择性进行乙酰化,而不会发生脱水或重排等竞争性副反应。催化剂的温和路易斯酸性质使乙酰化能够与光学活性底物一起进行,而不会对光学纯度产生任何不利影响。
Perchloric acid adsorbed on silica gel as a new, highly efficient, and versatile catalyst for acetylation of phenols, thiols, alcohols, and amines
作者:Asit K. Chakraborti、Rajesh Gulhane
DOI:10.1039/b304178f
日期:——
Perchloric acid adsorbed on silica gel efficiently catalyses acetylation of structurally diverse phenols, alcohols, thiols, and amines under solvent free conditions.
在无溶剂条件下,吸附在硅胶上的高氯酸可有效催化结构多样的酚,醇,硫醇和胺的乙酰化。
CuII-catalyzed regioselective borylation of alkynes and alkenes
作者:Shiwen Liu、Xiaojun Zeng、Bo Xu
DOI:10.1016/j.tetlet.2016.06.077
日期:2016.8
We developed a regioselective borylation of alkynes and alkenes protocol based on air-stable CuII/multi-dentate ligand system. Our catalytic system gives exclusive β-borylation products for most substrates in excellent chemical yields. We propose that multi-dentate electron poor nitrogen ligands can effectively discourage the formation of α-addition product through the steric hindrance and at same
我们开发了基于空气稳定的Cu II /多齿配体系统的炔烃和烯烃方案的区域选择性硼化。我们的催化系统以优异的化学收率为大多数底物提供独家的β-硼化产物。我们提出,多齿电子贫氮配体可以通过空间位阻有效地阻止α-加成产物的形成,同时保持良好的反应性。
An extremely fast and efficient acylation reaction of alcohols with acid anhydrides in the presence of trimethylsilyl trifluoromethanesulfonate as catalyst
作者:Panayiotis A. Procopiou、Simon P. D. Baugh、Stephen S. Flack、Graham G. A. Inglis
DOI:10.1039/cc9960002625
日期:——
Alcohols are converted to esters in a fast, clean and efficient reaction with acid anhydrides in the presence of trimethylsilyl trifluoromethanesulfonate.
在三甲基硅基三氟甲磺酸盐的存在下,醇与酸酐发生快速、干净且高效的酯化反应。
Palladium-Catalyzed [2+1] Cycloadditions Affording Vinylidenecyclopropanes as Precursors of 7-Membered Carbocycles
Palladium(II) acetate in association with secondary phosphine oxides provides an efficient catalytic system for [2+1] cycloadditions starting from oxanorbornene derivatives and tertiary propargyl esters giving rise to vinylidenecyclopropanes. This reaction is specific to bidentate phosphinito–phosphinous acid ligands generated from secondary phosphine oxides. The [2+1] cycloaddition was found broad