2001-49-2Relevant academic research and scientific papers
Why a proximity-induced Diels-Alder reaction is so fast
Krenske, Elizabeth H.,Perry, Emma W.,Jerome, Steven V.,Maimone, Thomas J.,Baran, Phil S.,Houk
scheme or table, p. 3016 - 3019 (2012/10/07)
Unlike normal Diels-Alder reactions of acyclic alkadienes with alkenes, the vinylbicyclo[2.2.2]octene employed in the Baran total synthesis of vinigrol undergoes a quantitative Diels-Alder reaction with a tethered alkene at room temperature. Density functional theory calculations reveal that this unprecedented reactivity originates from a combination of preorganization, diene strain, and tether stabilization.
The effect of pressure on cyclizations. The ring-size dependent reaction volumes of the cyclization of 1-alkenes to cycloalkanes. Experimental measurement of activation and reaction volumes of the intramolecular diels - Alder reaction of 1,3,8-nonatriene and 1,3,9-decatriene. Temperature dependence of activation and reaction volumes
Diedrich, Matthias K.,Kl?rner, Frank-Gerrit
, p. 6212 - 6218 (2007/10/03)
The volumes of reaction determined for the hypothetical cyclization of 1-alkenes to cycloalkanes decrease continUOusly from the formation of cyclopropane (ΔV(R) = -5.5 cm3 mol-1) up to the formation of cyclodecane (ΔV(R) = -32.3 cm3 mol-1) and seem to be constant for the larger rings. The analysis of the packing coefficients (η = V(w)/V) leads to the conclusion that this ring-size dependent decrease in volume results from the different packing of cyclic and acyclic compounds rather than from the changes in their intrinsic molecular volumes. The investigation of the intramolecular Diels-Alder reactions of (E)-l,3,8-nonatriene (E)-1 and (E)- 1,3,9-decatriene (E)-2 leading to the bicyclo[4.3.0]nonenes cis- and trans-4 (ΔV≠/ΔV(R) [cm3 mol-1] -24.8/-32.0 and -24.8/-28.5, respectively) or bicyclo[4.4.0]decenes cis- and trans-6 (-37.6/-45.4 and -35.0/-37.4, respectively) confirms the ring-size dependence of the activation and reaction volumes. The dependence of the effect of pressure from the number of newly forming rings is illustrated with the thermolysis of (Z)-1,3,8- nonatriene (Z)-1 in which an intramolecular Diels-Alder reaction leading to bicyclo [4.3.0]nonene cis-4 competes with a sigmatropic [1,5] hydrogen shift leading to (E,Z)-1,5,7-nonatriene 7. The use of high pressure causes a reversal of selectivity.
Experimental determination of the activation parameters and stereoselectivities of the intramolecular Diels-Alder reactions of 1,3,8-nonatriene, 1,3,9-decatriene, and 1,3,10-undecatriene and transition state modeling with the Monte Carlo-Jumping between Wells/molecular dynamics method
Diedrich, Matthias K.,Kl?rner, Frank-Gerrit,Beno, Brett R.,Houk,Senderowitz, Hanoch,Still, W. Clark
, p. 10255 - 10259 (2007/10/03)
Experimental activation parameters for the intramolecular Diels-Alder reactions of 1,3,8-nonatriene, 1,3,9-decatriene, and 1,3,10-undecatriene have been measured, and the Monte Carlo-Jumping between Wells/Stochastic Dynamics [MC(JBW)/SD] method, which gives relative free energies of activation, was tested as a means to predict stereoselectivities. The predictions are compared to experimental results, and to predictions from quantum and molecular mechanics methods.
Singlet and Triplet Excited-state Formation in High-energy Electron Tracks in Liquid cis- and trans-Decalin as studied by Product Formation in Radiolysis and Photolysis
Hummel, A.,Leng, H. C. de,Luthjens, L. H.,Wojnarovits, L.
, p. 2459 - 2466 (2007/10/02)
The yields of products formed as a result of irradiation of liquid cis- and trans-decalin with γ-rays and 3 MeV electrons as well as with 7.6 eV photons have been determined by means of gas-liquid chromatography (GLC).The major products for both cis- and trans-decalin are hydrogen, unsaturated C10 products and dimers; in the case of cis-decalin, cis-trans isomerization takes place via a chain reaction.Singlet and triplet excited states are formed by direct excitation and by charge recombination in the tracks of high-energy electrons.The product formation resulting from the singlets is determined by the photolysis.From a knowledge of the total yield of singlets from the radiolysis, the contribution of the singlet excited states to product formation during radiolysis is calculated and the remaining products are assigned to the triplets.For the sum of the yields of singlets and triplets a value of 6.4 (100 eV)-1 (=6.6E-7 mol J-1) is found for cis-decalin and 6.0 (100 eV)-1 (=6.2E-7 mol J-1) for trans-decalin and for the singlet fractions 0.53 and 0.47 in cis- and trans-decalin, respectively.The probability of C-H bond breakage in the singlet and triplet states is 0.42 and 0.82, respectively, for cis-decalin and 0.50 and 0.94, respectively, for trans-decalin.
Synthesis of the Pyrroloisoquinoline Substructure of the Manzamine Family of Alkaloids
Hart, David J.,McKinney, Jeffrey A.
, p. 2611 - 2614 (2007/10/02)
The first synthesis of the tricyclic pyrroloisoquinoline substructure of manzamines A, B, E and F is described.Reductive alkylation of benzoic acid followed by a 3-aza-6-heptenyl radical cyclization gave octahydroisoquinoline 9.An electrophile init
THERMAL REARRANGEMENTS OF CYCLIC ALLENES via RETRO-ENE REACTIONS
Price, John D.,Johnson, Richard P.
, p. 2499 - 2502 (2007/10/02)
Flow vacuum thermolysis (500-650 deg C) of 1,2-cyclonona- and 1,2-cyclodecadienes yields, as primary products, terminal enynes and enedienes.Secondary intramolecular Diels-Alder reactions of the enedienes afford cis and trans bicyclics.
Convenient Syntheses of Hydroindans and Hydronaphthalenes
Chou, Ta-shue,Tso, Hsi-Hwa,Chang, Lee-Jean
, p. 236 - 237 (2007/10/02)
Thermolysis of several new 2-(ω-alkenyl)-3-sulpholenes, prepared by direct deprotonation and alkylation of 3-sulpholenes, led to cheletropic extrusion of SO2 followed by intramolecular Diels-Alder reaction to yield the corresponding hydroindans and hydronaphthalenes.
INTRAMOLECULAR DIELS-ALDER REACTIONS 1,3,8-NONATRIENE AND 1,3,9-DECATRIENE
Lin, Yi-Tsong,Houk, K. N.
, p. 2269 - 2272 (2007/10/02)
The stereoselectivites of the title reactions have been investigated from 140-340 deg C, and relative activation parameters for cis and trans product formation have been determined.
INTRAMOLECULAR DIELS-ALDER REACTIONS OF DIENAMINES WITH ACRYLATES: TRENDS IN STEREOSELECTIVITY UPON SUBTITUTION
Wu, Tse-Chong,Houk, K. N.
, p. 2293 - 2296 (2007/10/02)
Intramolecular Diels-Alder reactions of all-trans ethyl 10-diethylamino-2,7,9-decatrienoate and 11-diethylamino-2,8,10-trienoate occur readily to produce trans and cis-fused products in ratios of 85:15 and 55:45, respectively.
Stereochemistry and Regiochemistry of Electron Impact Thermally and Photolytically Induced Eliminations from 2-Decalyl Acetates
Rej, R. N.,Taylor, C.,Eadon, G.
, p. 126 - 130 (2007/10/02)
Deuterium-labeled compounds are used to define the stereochemistry and regiochemistry of the electron impact induced elimination of acetic acid from trans,trans-2-decalyl acetate and trans,cis-2-decalyl acetate.Both compounds fragment with very predominant abstraction of equatorial hydrogen atoms.Since the trans equatorial hydrogens of the trans,trans acetate cannot be approached within the requisite 1.8 Angstroem by the acetate carbonyl in any boatlike conformer, this result demonstrates that hydrogen abstraction largely occurs from the chair conformer of the cyclohexyl ring.Both compounds fragment with predominant elimination toward C-1 rather than C-3.The regiochemistry of the pyrolysis of the acetates and the photolysis of the corresponding phenylacetates is compared with that of the mass spectral elimination.
