Diels -Alder reaction of butadiene

Sulfolane (tetramethylenesulfone) [126-33-0] M 120.2, m 28.5 , b 153-154 /18mm, 285 /760mm, d 1.263, n 1.4820. Prepared commercially by Diels-Alder reaction of 1,3-butadiene and sulfur dioxide, followed by Raney nickel hydrogenation. The principle impurities are water, 3-sulfolene, 2-sulfolene and 2-isopropyl sulfolanyl ether. It is dried by passage through a column of molecular sieves. Distd... 

Fig. 6.6. Relative energies of four possible transition structures for Diels-Alder reaction of 1,3-butadiene and propenal, with and without BF3 catalyst. Geometric parameters of the most stable transition structures (.endo-cis) are shown. Adapted from J. Am. Chem. Soc., 120, 2415 (1998), by permission of the American Chemical Society.

SCHEME 3. Comparison of van der Waals volumes of reaction and activation with the volumes of reaction and activation calculated for a pericyclic and stepwise Diels-Alder reaction of 1,3-butadiene with ethene... 

Prepared commercially by Diels-Alder reaction of 1,3-butadiene and sulphur dioxide, followed by... 

Hartman et al. [39,40], however, succeeded in preparing the exo-ortho adduct by Diels-Alder reaction of 1,3-butadiene with cyclobut-3-en-l,2-dicar-boxylic acid anhydride, hydrolysis of the anhydride, esterification, bromination of the double bond, dehydrobromination, ester hydrolysis, and re-formation of the anhydride (Scheme 6). 

The high simple diastereoselectivities seen in Figures 15.29 and 15.30 are due to the same preferred orientation of the ester group in the transition states. The stereostructure of the cycloadduct shows unequivocally that the ester group points underneath the diene plane in each of the transition states of both cycloadditions and not away from that plane. Figure 15.31 exemplifies this situation for two transition states of simple Diels-Alder reactions of 1,3-butadiene A shows a perspective drawing of the transition state of the acrylic acid ester addition, and B provides a side view of the addition of ethene, which will serve as an aid in the following discussion. Both structures were determined by computational chemistry. 

In 2006, two groups independently reported the novel asymmetric synthesis of tamiflu (106). Corey et al. reported a short enantioselective pathway for the synthesis of 106 from 1,3-butadi-ene and acrylic acid shown in O Scheme 22 [ 111 ]. The key steps of the synthesis are (1) Diels-Alder reaction of 1,3-butadiene (146) and trifluoroethyl acrylate (147) in the presence of chiral ligand 148 developed in the laboratory [112], (2) the introduction of two amino groups in tamiflu (106) without using potentially hazardous and explosive azide reagents, and (3) a novel S nBr4 - catalyzed bromoacetamidation. 

Wang, Y., Zeng, X.-l. Ab initio theoretical study of the hetero Diels-Alder reactions of 1,3-butadiene and furan with thioformaldehyde. Xinyang Shifan Xueyuan Xuebao, Ziran Kexueban 2002, 15, 177-180. 

Another way to prepare dibasic acids for the preparation of polyamides would be to oxidize cyclohexene from the Diels-Alder reaction of 1,3-butadiene and ethylene or cy-clooctene made from 1,3-butadiene by cyclic dimerization, followed by a reduction that might involve conjugation of the double bonds in situ (12.12). The latter may be preferable because the former requires forcing conditions.37 It may be possible to run the former reaction under high pressure or with ultrasound or with a metal complex catalyst (such as a metal triflate) to reduce the electron density of the diene by complexation. 

The benzoic acid might also be made by the Diels-Alder reaction of 1,3-butadiene with acrylic acid followed by catalytic dehydrogenation. Treatment of phenol with ammonia at high temperatures produces aniline, as mentioned in Chap. 2. Ethylbenzene can be rearranged to xylenes with zeolite catalysts. Thus, it could serve as a source of ph-thalic, isophthalic, and terephthalic acids by the oxidation of o, m, and p-xylenes. (The xylenes and other aromatic hydrocarbons can also be made by the dehydrocyclization of ethylene, propylene, and butenes, or their corresponding alkanes.44 Benzene can also be made from methane.195)... 

Table 3 Transition Structure Geometries, Activation Energies, and Reaction Energies of the Concerted Diels-Alder Reaction of 1,3-Butadiene and Ethylene...

According to the activation volume data the Diels-Alder dimerization of 1,3-butadiene [39] and o-quinodimethane (Table 2.5, entries (3) and (4), respectively) fall into the same class of concerted processes as those discussed for 1 and 7, while the Diels-Alder dimerization of hexamethylbis(methylene)cyclopentane seems to occur in stepwise fashion. According to the activation volume data summarized in Table 2.6 only the Diels-Alder reaction of 1,3-butadiene with a-acetoxyacrylonitrile seems to proceed concertedly while all other Diels-Alder and homo-Diels-Alder adducts are probably formed in stepwise processes comparable to the corresponding competitive [2 + 2] cycloadditions. Stereochemical investigations of the chloroprene and 1,3-butadiene dimerization using specifically deuterated derivatives confirm the conclusions drawn from activation volume data. In the dimerization of ( )-l-deuteriochloroprene (17) the diastereomeric Diels-Alder adducts ISa-Dz and... 

Fig. 10.7. Computed transition structures for uncatalyzed and BF3-catalyzed Diels-Alder reaction of 1,3-butadiene with methyl acrylate. Reproduced from Tetrahedron, 53, 6057 (1997), by permission of Elsevier.

The pericyclic reactions discussed to this point have been unimolecular rearrangements. The principles of conservation of orbital symmetry also apply to bimolecular cycloaddition reactions such as the Diels-Alder reaction. As shown in Figure 11.55(a), the Diels-Alder reaction of 1,3-butadiene with ethene produces cyclohexene. The analogous concerted cycloaddition of two ethene molecules to form cyclobutane. Figure 11.55(b), does not occur thermally, even though that reaction is calculated to be exothermic by 18 kcal/mol. ... 

It follows that the familiar Diels-Alder reaction of 1,3-butadiene and ethylene is an example of a transfer reaction in which the A fragment is transferred from the B to the C fragment. 

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