Peter W. Dibble

Furans and their Benzo Derivatives: Applications

This chapter provides an overview of literature from 1996 on the applications of various furan and benzofuran containing compounds. In addition to compounds that contain a furan or benzofuran ring the chapter includes various derivatives of these compounds that contain one oxygen atom within a five-membered ring, i.e., dihydro- and tetrahydrofuran ring, 2(5H)- and 3(2H)-furanones, five-membered anhydrides, isobenzofurans, dibenzofurans, benzofuranones, benzoanhydrides, polyarylfurans (and derivatives therefrom), and their hydro derivatives. Applications include pharmaceuticals, textiles and fibers, fossil fuels, dyes and photosensitizers, surface active agents and detergents, cellulose, lignin, paper and other wood products, leather, fats, waxes, essential oils, cosmetics, agrochemical bioregulators, pesticides, polymers, and polymer additives. Simple furan and benzofuran derivatives like tetrahydrofuran, maleic, succinic and phthalic anhydride, are not discussed in detail.

HIGH PRESSURE INTRAMOLECULAR DIELS-ALDER REACTIONS OF THE FURAN DIENE

Abstract A variety of substituted furans ( 1 - 6 ) undergo the intramolecular Diels-Alder reaction at high pressure (12.5 kbar) to provide oxatricyclo adducts ( 7 - 12 ) within 24 hours at room temperature.

Teraryls via phenylenebis(isobenzofuran) adducts

Abstract Arylisobenzofurans can be generated from hemiaminal precursors derived from the reaction of ortho-lithiated benzyl alcohol with 1,3- and 1,4-dicyanobenzene electrophiles. The bis(hemiaminal) products so formed give adducts formally derived from 1,4- and 1,3-phenylenebis(isobenzofuran). The adducts are easily aromatized to functionalized teraryl products.

Naphtho[1,2-c;5,6-c]difuran, a stable isobenzofuran derivative

Abstract The title compound, an interesting analog of isobenzofuran, was prepared in nine steps from 2,6-dimethylnaphthalene in an overall yield of 12%.

Stable phenylene- and biphenylene-bis(isobenzofuran)s related to diphenylisobenzofuran

A series of phenyl-substituted bis(isobenzofuran)s in which the furan moieties are linked by 1,3-phenylene, 1,4-phenylene, or 4,4′-biphenylene linkers have been prepared in only two steps. They are...

Ring-chain tautomerism of 1-hydroxyphthalans. An examination of structural effects

Abstract 1,3-Dihydro-1-isobenzofuranol,(1-hydroxyphtha1an) and 2-(hydroxymethyl)-benzaldehyde exist in a tautomeric equilibrium. The effects of molecular structure on this equilibrium was examined using various derivatives of dihydroisobenzofuranol. Two effects of this molecular modification were identified: (i) 1-arylmethyl substituents favored the ring-opened tautomer if steric effects arose in the ring closed form and (ii) extending the conjugated system of the dihydroisobenzofuran ring (i.e. dihydronaphtho[2,3-c] furan also favored the ring-opened form. These effects are discussed.

Phenanthro(2,3-c)furan—a stable benzologue of isobenzofuran with greater reactivity

Abstract Phenanthro[2,3- c ]furan, a benzologue of isobenzofuran has been isolated and found to be 15 times more reactive than isobenzofuran in agreement with extrapolated data of a linear Herndon relationship.

Steric and electronic effects in imine-hemiaminal ring-chain tautomerism

Abstract We have examined a series of 1,3-dihydro-1-isobenzofuranamines that exist in an imine/hemiaminal ring-chain tautomerism. The tautomeric free energies are rationalized in terms of electronic and steric effects. A series of compounds bearing substituents of varying bulk have free energies that correlate well with substituent A values.

X-ray structures of cyclophanes derived from naphtho[1,2-c:5,6-c]difuran and the synthesis, structure, and reaction kinetics of its 1,3,6,8-tetrasilylated derivative.

A silylated derivative of naphtho[1,2-c:5,6-c]difuran, 1,3,6,8-tetrakis(tert-butyldimethylsilyl)naphtho[1,2-c:5,6-c]difuran, has been isolated and its X-ray crystal structure determined. Bond localization confirms the polyene character of this isobenzofuran ring system. This molecule undergoes two successive Diels-Alder reactions with second-order rate constants differing by over 2 orders of magnitude, consistent with predictions based on their structure-count ratios and with the reactivity of the novel 1,3-bis(tert-butyldimethylsilyl)isobenzofuran. Crystal structures of two cyclophanes derived from the reaction of naphtho[1,2-c:5,6-c]difuran and bis(imide) or bis(ester) dienophiles show marked differences in the conformation of the aliphatic chain found in the solid state.

(2R,3aR,4S,7R,7aS,9R,10aR,11S,14R,14aS)-rel-3a,4,7,7a,10a,11,14,14a-Octa­hydro-4,14:7,11-diep­oxy-2,9-propanona­phtho[1,2-f:5,6-f′]diisoindole-1,3,8,10-tetrone (9CI): a cyclo­phane derived from naphtho[1,2-c:5,6-c]difuran

The title compound, C25H18N2O6, is a naphthalenophane styled in the manner of Warrener’s alicyclic cyclophanes or molecular racks wherein a trimethylene tether is perfectly staggered between the two N atoms such that the central methylene H atoms point toward the naphthalene π-system. The dihedral angle between the mean planes of the two benzene rings is 7.61 (7)°.