Furfuryl fumarates

High-pressure and thermally induced intramolecular Diels-Alder reactions of furfuryl fumarates. Influence of tether substituents on diastereoselectivity [74]... 

The use of isopropylidine acetals (112) as tethers in the intramolecular Diels-Alder reactions of dienes with alkenes facilitates the formation of civ-fused cycloadducts (113) from an endo transition state (Scheme 41).218 The intramolecular Diels-Alder reaction of 4-[tris-(2-mcthylcthyl)silyl]oxy-2//-thiopyran derivatives with potential dienophiles tethered at C(2), C(3), C(5), and C(6) positions yielded cycloadducts when the dienophiles were activated with a carbomethoxy group.219 By the substitution of a phenylsulfonyl group on the dienophile of 2-benzopyran-3-ones, it is possible to enhance exo addition during intramolecular Diels-Alder cyclizations to yield a predominance of trans-fused hexaphenanthrenes related to natural products.220 The intramolecular Diels-Alder reaction of 2-furfuryl fumarates has been investigated by molecular mechanics (SIBFA)/continuum reaction field computations.221 The intramolecular 4 + 2-photo-cycloaddition of A-benzylcinnamamides (114) in the presence of C(,H6 gives 3-azatricyclo[5.2.2.01,5]undeca-8,10-dien-4-ones (115) with high stereoselectivity (Scheme 42).222... 

Scheme 27 Asymmetric IRDARs of furfuryl fumarates 91 under thermal and high-pressure conditions [65]...

Asymmetric IRDARs of optically active furfuryl fumarates 91 were investigated under thermal and high-pressure conditions. The diastereoselectivities observed increased with the size of the tether substituents, achieving up to 86% in the case of R = f-Bu, though in the case of R = neo-Pen only 38% de was obtained. It is concluded the diastereoselectivity observed was thermodynamically controlled (Scheme 27) [65]. An IRDA ring-expansion approach toward taxinine (a carbocylic compound) [66] utilizing both Lewis acids and high pressure has been reported [67]. 

Butz and Sauer investigated the intramolecular Diels-Alder reaction of furfuryl fumarates 148 to synthesize oxabicyclo[2.2.1]heptene derivatives 149 and 150 (Scheme 8.37) [69]. Four new stereocenters of defined configuration are generated in this transformation under the induction of the stereogenic center in the side arm with remarkable selectivity. The cycloaddition of 148 with various substituents R at the stereogenic center was investigated and it was found that the diastereo-... 

Scheme 8.37. Intramolecular Diels-Alder reactions of furfuryl fumarates.

Another example of an enzymatic one-pot multiple Diels-Alder reaction is illustrated in Table 4.20 [83]. Racemic furfuryl alcohols 130 in the presence of ethoxy vinyl methyl fumarate 131 and enzyme TOYOBO-LIP undergo enzymatic acylation followed by kinetic enzymatic resolution to give the acyl derivatives 132 which then affords the adducts 133 and 134 by intramolecular Diels-Alder reaction 3-methyl-furfuryl alcohol 130 (R = Me) in acetone gives the best results. 

Rather large rate enhancements with increasing solvent polarity have also been found for intramolecular Diels-Alder reactions such as the cyclization of 2-furfuryl methyl fumarate shown in Eq. (5-42a) to yield lactone D. This first-order reaction is about 3200 times faster in dimethyl sulfoxide than in toluene as solvent [807]. 

Formaldehyde/toluenesulfonamide polymer Formamide Fumaric acid Furfural Furfuryl alcohol... 

Ferric chloride . Ferric chloride hexahydrate Ferric sulfate Ferrous gluconate Ferrous gluconate dihydrate Fumaric acid Furfuryl mercaptan... 

Furfuryl alcohol phenolic resin comonomer Bisphenol A phenolic resin mfg. p-t-Amylphenol Tall oil rosin phenolic resin modifier Cumyl phenol Fumaric acid phenolic resins Phenol... 

Jung ME, Gervay J. gem-Dialkyl effect in the intramolecular Diels-Alder reaction of 2-furfuryl methyl fumarates the reactive rotamer effect, the enthalpic basis for acceleration, and evidence for a polar transition state. //lm Chem Soc. 1991 13(1) 224—232. 

Trade Names Containing Acti-Gel 208 Fumaric resin. See Maleic resin Fumed silica Fumed silicon dioxide. See Silica, fumed Fural 2-Furaldehyde Furale 2-Furanaldehyde. See Furfural 2-Furancarbinol. See Furfuryl alcohol 2-Furancarbonal 2-Furancarboxaldehyde. See Furfural... 

---