Mild thermolysis of tert-butyl alkynyl ethers furnishes aldoketenes, which undergo facile [2 + 2] cycloaddition reactions with pendant di- and trisubstituted alkenes. A wide variety of cis-fused cyclobutanones are produced in moderate to high diastereoselectivity and good to excellent yields by this method, and free hydroxyl groups are tolerated in the ene-ynol ether starting materials. Enol-yn...

Benzylic alcohols and ethers are common subunits in bioactive molecules, as well as useful intermediates in organic chemistry. In this Communication, we describe a new approach to the enantioselective synthesis of benzylic ethers through the chiral phosphine-catalyzed coupling of two readily available partners, γ-aryl-substituted alkynoates and alcohols, under mild conditions. In this process, ...

SYNLETT 2007, No. 17, pp 2695–269816.10.2007 Advanced online publication: 25.09.2007 DOI: 10.1055/s-2007-991068; Art ID: U07007ST © Georg Thieme Verlag Stuttgart · New York Abstract: A novel synthetic method for the preparation of various alkyl ethers is described. The reaction between alkyl halides and sodium hydride in the presence of N,N-dimethylformamide afforded the corresponding symmetric...

2-Benzyloxy-1-methylpyridinium triflate (1) is emerging as a mild, convenient, and in some cases uniquely effective new reagent for the synthesis of benzyl ethers and esters. This article provides a revised benzyl transfer protocol in which N-methylation of 2-benzyloxypyridine delivers the active reagent in situ. Observations on the appropriate choice of solvent (toluene vs. trifluorotoluene) a...

The trimethylsilyl ethers of alditols with 3, 4, 5 and 6 carbon atoms were investigated. The mass spectra are unusually clearly correlated with the structures. The predominant fragmentations are cleavages in the carbon chain and rearrangement loss of trimethylsilanol. The spectra are closely related to those of the methyl ethers. A spectrum unambiguously identifies a compound as an alditol and ...

A variety of functionalized 3,4-benzo-7-hydroxy-2,9-diazabicyclo[3.3.1]non-7-enes were prepared by one-pot cyclizations of 1,3-bis(silyl enol ethers) with quinazolines. The mechanism of the cyclization was studied by B3LYP/6-31G(d) density functional theory computations. The products could be functionalized by Suzuki cross-coupling reactions. The reaction of 1,3-bis(silyl enol ethers) with phth...

Ten single benzyl phenyl ethers were synthesized and evaluated as human immunodeficiency virus-1 (HIV-1) inhibitors in vitro for the first time. Among these compounds, especially 4-nitrobenzyl phenyl ether (3h) exhibited the highest anti-HIV-1 activity with EC50 (concentration of drug that reduces syncytia formation by 50%) value of 5.96 microg/ml and therapeutic index value of 18.32. The preli...

[reaction: see text]. Synthesis of novel dithiane-spiro-crown ethers starting from 5,5-di(hydroxymethyl)-1,3-dithiane is developed. These compounds can be used as building blocks to assemble photolabile bis-crown ethers via addition to dicarbonyl-containing tethers, e.g., isophthalic aldehyde. It is found that unlike their mono-crown precursors such bidentate bis-crowns are capable of efficient...

One of the most well-known, highly utilized reagents for ether cleavage is boron tribromide (BBr3), and this reagent is frequently employed in a 1:1 stoichiometric ratio with ethers. Density functional theory calculations predict a new mechanistic pathway involving charged intermediates for ether cleavage in aryl methyl ethers. Moreover, these calculations predict that one equivalent of BBr3 ca...

ESR Signals, Spin-Trapping, N itro/N on-N itro Diphenyl Ethers, Chloroplasts, Electron Transport Phenyl-/-butylnitrone can be used to trap light-induced radicals with isolated chloroplasts, measurable by ESR technique. The radical signals are dramatically am plified and their lifetim e prolonged in the presence of peroxidizing diphenyl ethers. A pora-substitution with —N 0 2, —Cl or I is necess...