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ortho‐Carbonylarylacetylenol, can be utilized for the synthesis of several important core structures. In this work, a method is developed for the diastereoselective synthesis of spirocyclic ethers using a silver catalyst under the presence of acid. This protocol can be applied to a variety of substrates resulting in the corresponding products in 35–97% yields with good diastereoselectivity. The proposed reaction mechanisms and stereoselectivity outcome of the corresponding products are investigated using DFT calculation. This current protocol can be applied to a broad range of substrates which would be useful for the creation of libraries of spirocylic ethers [ABSTRACT FROM AUTHOR]

Bromohydrins and their ethers were electrochemically synthesized via hydroxy‐ and alkoxybromination of alkenes using potassium bromide and water or alcohols. High selectivity of bromohydrins formation was achieved only with the use of DMSO as the solvent and an acid as the additive. The proposed combination of starting reagents, additives, and solvents allowed to form bromohydrins or their ethers selectively despite the variety of side‐products (epoxides, dibromides, diols). Bromohydrins were obtained in high yields, up to 96%, with a broad substrate scope in an undivided electrochemical cell equipped with glassy carbon and platinum electrodes at high current density. [ABSTRACT FROM AUTHOR]

This review presents an update on the emerging field of enantioselective multicatalyzed tandem reactions published since the beginning of 2015. It illustrates how much the combination of different types of catalyst allows unprecedented enantioselective one‐pot reactions of many types to be achieved, allowing a direct access to a variety of very complex chiral molecules. Abbreviations: acac: acetylacetonate; Ar: aryl; Bn: benzyl; Boc: tert‐butoxycarbonyl; BPE: 1,2‐bis(2‐pyridyl)ethane; Bz: benzoyl; CAPT: chiral anion phase‐transfer; Cbz: benzyloxycarbonyl; cod: cyclooctadiene; Cy: cyclohexyl; dba: (E,E)‐dibenzylideneacetone; DBU: 1,8‐diazabicyclo[5.4.0]undec‐7‐ene; DCE: dichloroethane; de: diastereomeric excess; DIPEA: diisopropylethylamine; dme: 1,2‐dimethoxyethane; DPG: 1,3‐diphenylguanidine; dppe: 1,2‐bis(diphenylphosphino)ethane; ee: enantiomeric excess; EWG: electron‐withdrawing group; Hept: heptyl; Hex: hexyl; L: ligand; MTBE: methyl tert‐butyl ether; MOM: methoxymethyl; MS: molecular sieves; Naph: naphthyl; NHC: N‐heterocyclic carbene; Pent: pentyl; Phth: phthaloyl; pin: pinacolato; Pybox: 2,6‐bis(2‐oxazolyl)pyridine; r.t.: room temperature; TEMPO: 2,2,6,6‐tetramethylpiperidine 1‐oxyl; Tf: trifluoromethanesulfonyl; THF: tetrahydrofuran; TMP: 2,2,6,6‐tetramethylpiperidine; TMS: trimethylsilyl; Tol: tolyl; triphos: bis(diphenylphosphinoethyl)phenylphosphine; Ts: 4‐toluenesulfonyl (tosyl). [ABSTRACT FROM AUTHOR]

An efficient chlorination of indoles and electron‐rich arenes with chlorine anion as nucleophile is described. With the use of ethyl phenyl sulfoxide as the promoter, the reaction went smoothly under metal‐free and mild conditions. Various indoles and electron‐rich arenes are converted into the corresponding chlorinated compounds in moderate to excellent yields. A plausible interrupted Pummerer reaction mechanism was proposed without the oxidation of chloride anion. In addition, the byproduct thioether could be easily converted to the starting material sulfoxide just by a simple oxidation reaction. [ABSTRACT FROM AUTHOR]

Amine containing aryl ethers are common pharmacophore motifs that continue to emerge from drug discovery efforts. As amino alcohols are readily available building blocks, practical methodologies for incorporating them into more complex structures are highly desirable. We report our efforts to explore the application of Pd‐catalyzed C−O coupling methods to the arylation of 1,2‐ and 1,3‐amino alcohols. We established general and reliable conditions, under which we explored the scope and limitations of the transformation. The insights gained have been valuable in employing this methodology within a fast‐moving drug discovery environment, which we anticipate will be of general interest to the synthesis and catalysis communities. [ABSTRACT FROM AUTHOR]

Herein, we describe a synthetic approach for arylation that exploits the in situ formation and reaction of an unsymmetrical diaryliodonium salt. In this way, aryl iodides are used as reagents in a metal‐free reaction with phenols, and a trimethoxyphenyl (TMP) group is used as a "dummy" group to facilitate transfer of a wide range of aryl moieties. The scope of aryl electrophiles and phenol nucleophiles is broad (>30 examples) and the yields are high (52–95%, 80% avg.). One‐pot coupling reactions avoid the synthesis of diaryliodonium salts and provide opportunities for sequential reactions and novel chemoselectivity. [ABSTRACT FROM AUTHOR]

Ni‐catalyzed C−O(Py) bond activation and silylation of aryl 2‐pyridyl ethers with silylzinc chlorides were carried out. This protocol allowed the 2‐pyridyloxy group to be substituted by a silyl group with short reaction times, mild reaction conditions, and good compatibility of functional groups. [ABSTRACT FROM AUTHOR]

A direct and simple strategy to heteroaryl ethers via a visible‐light‐induced alkoxylation of quinoxalin‐2(1H)‐ones with alcohols under ambient conditions was developed. The commercially available, low cost alcohols served as alkoxylation reagents and solvents. This reaction has advantages of novel protocol, mild conditions, good functional‐group tolerance, and high yields of products. [ABSTRACT FROM AUTHOR]

An approach to preparing enynyl‐aryl ethers from phenols and phenylacetylenes is described. This method without extra ligands, overcoming the favored Glaser‐Hay dimerization of alkyne, features a wide substrate scope (38 examples including endofolliculina and indole) and the merits of high atom and step economy, good regio‐ and stereoselectivity (Z‐isomers major) in moderate to good isolated yields. Mechanistic studies show that the reaction is enabled by distinctive copper/iodide tandem catalysis. [ABSTRACT FROM AUTHOR]

The one‐pot synthesis of symmetrical and unsymmetrical ethers from aldehydes and ketones can be conveniently performed using Yb(OTf)3 as catalyst and triethylsilane as reducing agent in presence of alcohols. This methodology leads to the synthesis of ether derivatives with good yields. Notably, this process resulted a useful tool to protect alcohols as benzyl ether derivatives using differently substituted benzaldehydes as protecting agents under mild conditions. A plausible mechanism was also proposed. [ABSTRACT FROM AUTHOR]

Malonyl peroxides act both as oxidants and reagents for C−O coupling in reactions with methyl and silyl enol ethers. In the proposed conditions, the oxidative C−O coupling of malonyl peroxides with enol ethers selectively proceeds, bypassing the traditional Rubottom hydroxylation of enol ethers by peroxides. It was observed that the oxidative [5+2] cycloaddition of malonyl peroxides and enol ethers is the key stage of the discovered process. Oxidative C−O coupling of silyl enol ethers leads to the formation of α‐acyloxyketones with a free carboxylic acid group. A specially developed preparative one‐pot procedure transforms ketones via silyl enol ethers formation and the following coupling into α‐acyloxyketones with yields 35–88%. The acid‐catalyzed coupling with methyl enol ethers gives remarkable products while retaining the easily oxidizable enol fragment. Furthermore, these molecules contain a free carboxylic acid group, thus these nontrivial products contain two usually incompatible acid and enol ether groups. [ABSTRACT FROM AUTHOR]

Abstract: We report the palladium/Brønsted acid co‐catalyzed formal insertion of carbene into the C−O or C−N bond of 2H‐chromene acetals or hemiaminal ethers. This transformation was initiated by the Brønsted acid‐promoted cleavage of the C−O or C−N bond, followed by modification of the leaving alcohol or amino fragments with palladium carbenes, and reassembly of the modified fragments. A variety of C‐2 functionalized 2H‐chromene derivatives were obtained in moderate yield (43∼75%) with good to excellent diastereoselectivities (up to >95:5 dr) under mild conditions. [ABSTRACT FROM AUTHOR]

Abstract: A simple halogen‐bond‐promoted α‐C−H amination of ether/thioether with a variety of N−H compounds has been accomplished. In the presence of low‐cost and readily available perfluorobutyl iodide, a diverse range of hemiaminal ether derivatives, including the valuable hydrazone hemiaminal ethers, were quickly assembled under thermal or visible‐light irradiation conditions. Mechanistic studies suggest that a halogen‐bond adduct was formed and a radical chain pathway might be operative. Synthetic application of the method has been demonstrated via the preparation of the anti‐viral and anti‐tumor drug, Tegafur. [ABSTRACT FROM AUTHOR]

An efficient and selective approach to the synthesis of selenide ethers containing one or two geminal C-Se bonds from readily available diselenides and phenylacetic acids was developed. Compounds containing one C-Se bond were prepared by employing air as the oxidant under metal-free conditions, whereas compounds having two geminal C-Se bonds were formed via the iron(III) chloride/oxygen/cesium carbonate (FeCl3/O2/Cs2CO3) system. Moreover, 1,2-diphenyldisulfane also could be smoothly converted into the corresponding sulfur ether product under the standard reaction conditions. [ABSTRACT FROM AUTHOR]

A synthesis of tricyclic oxoisochromene derivatives via an intramolecular direct arylation of cycloalkyl-1,3-diketone-derived α,β-unsaturated ketone substrates is described. Interesting mechanistic insight has been gathered, based on deuterium migration studies, induced by palladium (Pd). [ABSTRACT FROM AUTHOR]

The three-component reaction of α-halomethyl oxime ethers, boronic acids and carbon monoxide at atmospheric pressure catalyzed by tetrakis(triphenylphosphine)palladium(0) gives efficiently unsymmetrical β-alkoxyimino carbonyl compounds with total control of the regioselectivity, in high yield and atomic economy. Simple commercially available starting materials are used in this synthetic procedure. The three components assembly takes place preferentially versus the competing direct coupling or other possible side reactions. The mechanism of the transformation was investigated by NMR and intermediate palladium(II) complexes were detected. [ABSTRACT FROM AUTHOR]

A one-pot, two-step catalytic protocol for the preparation of cinnamyl ethers from simple and readily available aryl halides, phenols and allyl chloride is reported for the first time. This simple and highly efficient palladium nanoparticles catalytic system shows good regio- and stereoselectivities and affords the desired products in good to high yields (49-85%) from aryl iodides. Furthermore, less reactive aryl bromides can also give the cinnamyl ethers in moderate yields (24-72%). [ABSTRACT FROM AUTHOR]