POV-based molecular catalysts for highly efficient esterification of alcohols with aldehydes as acylating agents

The selective oxidative esterification of aldehydes with alcohols to the corresponding esters has been one of the hot spots in scientific research and industrial synthesis.However,the application of precious metal catalytic systems is limited by their complicated synthetic steps and high cost.Thus a highly efficient,green,recyclable selective synthesis method of esters catalyzed by polyoxovanadate(POV)-based molecu-lar catalysts has been developed in this paper.The results show that supramolecular interaction between POV and 1,3-dibenzylimidazolium bromide(Act_(2)Im)can efficiently convert alcohols and aldehydes to the corresponding esters in high yield under much milder conditions.Mechanistic insight is also provided based on the control experiments,single crystal X-ray diffraction and cyclic voltammetry studies.

Additive-Mediated Selective Oxidation of Alcohols to Esters via Synergistic Effect Using Single Cation Cobalt Catalyst Stabilized with Inorganic Ligand

The direct catalytic oxidation of alcohols to esters is very appealing,but the economical-friendly catalysis systems are not yet well established.Herein,we show that a pure inorganic ligand-supported single-atomic cobalt compound,(NH_(4))_(3)[CoMo_(6)O_(18)(OH)_(6)](simplified as CoMo_(6)),could be used as a heterogeneous catalyst and effectively promote this type of reaction in the presence of 30%H_(2)O_(2)using KCl as an additive.The oxidative cross-esterification of various alcohols(aromatic and aliphatic)could be achieved under mild conditions in nearly all cases,affording the corresponding esters in high yields,including several drug molecules and natural products.Detailed studies have revealed that chloride ion is able to bind to the CoMo_(6)to form a supramolecular dimer 2(CoMo_(6)∙Cl),which can effectively catalyze the reaction via a synergistic effect from chloride ion and CoMo_(6).Mechanism studies and control reactions demonstrate that the esterification proceeds via the key oxidative immediate of aldehydes.