Copper‐Catalyzed Formation of C–O Bonds by Oxidative Coupling of Benzylic Alcohols with Ethers

Abstract

The copper‐catalyzed formation of C–O bonds by oxidative coupling of benzylic alcohols with ethers was realized in open air. A series of α‐acyloxy ethers were obtained in good yields with aqueous tert‐butyl hydroperoxide as the oxidant.

An Efficient, Eco-friendly and Sustainable One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Directly from Alcohols Catalyzed by Heteropolyanion-Based Ionic Liquids

“…Based on our previous investigations into HPAILs catalyzed reactions [ 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 , 112 ], N -substituted imidazole, pyridine and triethylamine based HPAILs were chosen as potential catalysts for this tandem oxidative cyclocondensation ( Figure 1 ).…”

“…Recently, a large number of publications have clearly shown that the main benefit of microwave (MW) chemical processing is the significant rate enhancements, yield and selectivity improvements as well as less environmental pollution, matching with the goals of green chemistry [ 100 , 101 , 102 ]. Following our continued investigation into the development of useful and sustainable synthetic methodologies [ 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 ]—along with recent investigations involving oxidation of alcohols and the subsequent trapping of carbonyl intermediates with appropriate nucleophiles in a one-pot operation. [ 112 ]—herein, we report an efficient and environmentally benign TOPs for the Biginelli reaction, starting directly from alcohols, using HPAILs as catalysts and NaNO 3 as an oxidant under MW and solvent-free conditions ( Scheme 1 ).…”

Copper-Catalyzed Oxidation of Alkenes and Heterocycles

“…Fu, Yuan, et al recently disclosed the copper-catalyzed formation of C-O bonds by oxidative coupling of benzylic alcohols with ethers employing a 70% aqueous TBHP solution as the oxidant in air. 58 Other oxidants, such as DDQ, NaClO, H 2 O 2 , O 2 , m-chloroperbenzoic acid, did not show any activity. The molar ratio of reagents was very important, and an excess of the TBHP (6.0 equiv) and the ether (60 equiv) had to be employed (Scheme 19, a).…”

Far Away from Flatland. Synthesis and Molecular Structure of Dihetera[3.3.n]propellanes and Trihetera[3.3.n]propellanes: Advanced Analogues of Morpholine/Piperazine

“…However, the simplest representatives of oxa-/aza [3.3.n]propellanes (n = 2−4) were not described in the literature despite promising conformationally restricted analogues of widespread heteroaliphatic amines (i.e., morpholine and piperazine). 8,9 It should be outlined that such three-dimensional sp 3 -enriched, lowmolecular weight building blocks are of high demand in drug discovery as a tool for improving physicochemical properties, fine-tuning binding with biological targets, or reducing offtarget activity. 10−13 Known synthetic approaches to oxapropellanes relied on the construction of the tetrahydrofuran ring via reduction of the corresponding bicyclic dicarboxylic acid derivatives, followed by intramolecular cyclization of the resulting diol (Scheme 1, method A).…”

“…Over the history of organic chemistry, molecules with unusual three-dimensional structures have frequently attracted the attention of chemists as possible synthetic targets. − Among such structures, propellanes (tricyclo­[m.n.p.0 x,y ]­alkanes) containing three rings fused by one C–C axis are one of the most recognizable . The term “propellane” was coined by David Ginsburg in 1966; he had been the main contributor to tricycloalkane chemistry with more than 100 publications and a monograph. , Since then, the smallest representative (tricyclo­[1.1.1.0 1,3 ]­pentane) became the object of extensive study, while larger derivatives were scarcely reported .…”