The transition metal-catalyzed allylic substitution of unactivated allylic substrates (allylic alcohols, allylic ethers and allylic amines) is rapidly becoming an important area of research. There are several advantages to using these substrates in allylic substitution reactions: the use of unactivated alcohols minimizes the production of waste by-products and reaction steps; and allylic ethers...

We report the cross-dehydrative reaction of two alcohols to form unsymmetrical ethers using NHC–gold(I) complexes (NHC = N-heterocyclic carbene). Our progress in developing this reaction into a straightforward procedure is discussed in detail. The optimised methodology proceeds under mild reaction conditions and produces water as the sole by-product. The synthetic utility of this environmentall...

A trinuclear gold(I)-oxo complex, [(Ph3PAu)3O]BF4, serves as the catalyst for the stereocontrolled synthesis of 2-hydroxy-3,6-dihydropyrans from propargyl vinyl ethers. Importantly, the rearrangement proceeds with excellent diastereoselectivity, and the rearrangement of chiral nonracemic propargyl vinyl ethers proceeds with excellent chirality transfer to furnish enantioenriched pyrans. Additio...

A series of chalcone-based macrocyclic ethers have been synthesized. These macrocyclic ethers contain polyether as well as extended conjugation to the benzene ring to function as fluorescent sensor for cations. The modeling studies show that the chalcone part of the receptors remains partially out of plane from the polyether part and the keto moiety of the receptors always directed outwardly in...

N,N'-bis(bromobenzyl) and N,N'-bis(halopyridinyl) derivatives of diaza-12-crown-4, diaza-15-crown-5 and diaza-18-crown-6 ethers were synthesized in high yields. The Pd-catalyzed macrocyclization reactions of these compounds were carried out using a variety of polyamines and oxadiamines were carried out to give novel macrobicyclic and macrotricyclic compounds of the cryptand type. The dependence...

Kinetic investigations of substituent effects in the thermal rearrangement of bis-vinyl ether substrates are reported. Findings indicate that the influence of the various substituent patterns on the rate of rearrangement in these compounds differs from that documented in the literature for the analogous [3,3]-sigmatropic rearrangement of allyl vinyl ethers. In addition, the thermochemical data ...

A mechanistic study of arylations of aliphatic alcohols and hydroxide with diaryliodonium salts, to give alkyl aryl ethers and diaryl ethers, has been performed using experimental techniques and DFT calculations. Aryne intermediates have been trapped, and additives to avoid by-product formation originating from arynes have been found. An alcohol oxidation pathway was observed in parallel to ary...

The synthesis, complexation properties and catalytic activities under phase-transfer (PT) conditions of differently substituted cyclohexapeptoids are reported. Association constants, for small cationic alkali, and catalytic performances, in a model nucleophilic substitution, are comparable to those of representative crown ethers. Noteworthy, the N-[2-(2-methoxyethoxy)ethyl] side chain derivativ...

A chiral Brønsted acid has been developed from a cationic gold(I) disphosphine complex in the presence of alcoholic solvent and applied to the enantioselective protonation reaction of silyl enol ethers of ketones. Various optically active cyclic ketones were obtained in excellent yields and high enantioselectivities, including cyclic ketones bearing aliphatic substrates at the α-position. Furth...

The synthesis and spectroscopic investigation of aza-crown ethers with anthraquinoneand 1-aminoanthraquinone-functionalized side chains are described. Cation-induced shifts in the UV/VIS absorption spectra of the ligands dissolved in propylene carbonate are observed only for Li+ among the alkali metal ions and for Mg2+ among the alkaline earth metal ions as well as for Ag+ and T1+. Only hypsoch...