Furan 2-vinyl-dihydro

There are several reports scattered in the literature of the retarding effect of simple furan derivatives in the polymerization of a specific monomer. Hardy69, U6 found that furan, 2-furoic acid and its esters, and 5-substituted-2-furoie acids were strong retarders in the radical polymerization of vinyl acetate, but did not act likewise with styrene. He proposed that as a result of the reactions of the free radicals with the furan derivatives, dihydro- and tetrahydrofurans would form, but he did not produce any evidence to support these speculations. Clarke, Howard and Stock-... 

Azadienes undergo Diels-Alder reactions to form pyridine, dihydro- and tetrahydropyridine derivatives. N-Vinyl lactim ethers undergo Diels-Alder reactions with a limited set of dienophiles. " Thioketones react with dienes to give Diels-Alder cycloadducts. The carbonyl group of lactams have also been shown to be a dienophile. Certain heterocyclic aromatic rings (among them furans) can also behave as dienes in the Diels-Alder reaction. Some hetero dienes that give the reaction are -C=C-C=0, 0=C-C=0, and N=C-C=N. ... 

Benzenediamine (355) and 3-bromomethyl-4-methyl-2,5-dihydro-2,5-furan-dione (2-bromomethyl-3-methylmaleic anhydride 356) gave 3-(l-carboxy-vinyl)-3-methyl-3,4-dihydro-2( 1 //)-quinoxalinone (357) with loss of hydrogen bromide (CHCI3, — 15°C >20°C, 4 h 86%) a rational mechanism was proposed.625... 

DIENOPH1LES Acrolein. Ethynylp-tolyl sulfonc. 3-Mcthylsulfony 1-2,5-dihydro-furane. 3-Nitro-2-cyclohexenone. Phenyl vinyl sulfone. 

Wahrend 2.5-Dihydro-furan in Benzol durch ein Vycor-Filter bestrahltzuFuran und Tetra-hydrofuran disproportioniert, bildet sich in Ather, Methanol oder Cyclohexan zusatzlich Vinyl-oxiran ( 10% bez. auf umgesetzen Ather)6 ... 

Reaction with phosphorus compounds. Hydrozirconation of vinyl(diphenyl)-phosphine at C-l is feasible, while ring cleavage of l-phenylphospha-3-cyclopentene to give homoallylic phosphines is observed. (l-Benzyl-3-pyrroline and dihydro-furan also undergo similar cleavage.)... 

The fluorination of perchloro-2,5-dihydrofuran with antimony triiluoride and mixed antimony halides gives all the possible chlorofluoro-2,5-dihydro-furans formed by successive replacement of the allylic chlorine atoms fluorination in anhydrous hydrogen fluoride results in the formation of only trichloro-2,2,5-trifluoro- and dichloro-2,2,5,5-tetrafluoro-2,5-dihydrofuran. Potassium fluoride in iV-methyl-2-pyrrolidone replaces both vinylic and allylic chlorine atoms, giving 2,2,4-trichloro-3,5,5-trifluoro- (5%) and per-fluoro-2,5-dihydrofuran (49%). ... 

Bisdiazaphospholanes have been linked to organic resins via the correspond-ingtetraacyl fluoride derivatives (Scheme 2.147) [69]. Compared with the relevant homogeneous catalysts, comparable regio- and enantioselectivities were observed in the AHF of styrene, vinyl acetate, 0-silyl protected allyl ethers, and dihydro-furane. Excellent recyclability with only trace levels of rhodium leaching were reported under batch or flow conditions. In contrast, the silica-bound catalyst I exhibited poorer enantioselectivities. 

Atbyl-4.5-dibydTO-fanui 17 113. 2-Athyl-2.5-dihydro-furan oder 2-Vinyl-... 

Other related reagents are y-butyrolactone, dihydro-5-(hydroxymethyl)-2(3//)-furanone, 2,5-dihydro-2,5-dimethoxy-furan, furan, 5-lithio-2,3-dihydrofuran, and /3-vinyl-a,/3-butenolide. 

Reactions. Birch reduction of 2-furoic acid with lithium in liquid ammonia gives the 2,5-dihydro-compound (131) in 90% yield. Hydrogenation of the vinyl-furans (132 R = CO2H, C02Me, Ac, or COPh) in the presence of nickel bromide occurs selectively at the exocyclic double bond. Anodic methoxylation of 2-(2-thienylmethyl)-furan yields a mixture of geometrically isomeric adducts... 

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