Reactions of isoprenoids. XII. 1,4-Cycloaddition reactions of nitrosobenzene with isoprene, chloroprene, and myrcene

Sasaki, Tadashi; Eguchi, Shoji; Ishii, T.; Yamada, H.

doi:10.1021/jo00837a013

Cited by 12 publications

(3 citation statements)

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“…Only isomer A has been said to be obtained by reaction of isoprene (R 1 = H) with either nitrosobenzene or p -chloronitrosobenzene . Under our conditions, reaction of nitrobenzene with isoprene gave indeed 4A as the largely dominating isomer, as determined by comparison of the 1 H NMR spectrum with the one reported in the literature for this compound, but some low-intensity signals were also present, which could not be attributed to any known compound and which are close to the ones of 4A and can be attributed to the previously undetected minor isomer 4B .…”

Section: Resultssupporting

confidence: 59%

“…The byproducts azo- and azoxybenzene, diphenylurea, and all anilines are commercial products and were identified by comparison of their CG or HPLC chromatograms and GC-MS spectra with those of authentic samples. 1,3,5-Triphenyl-[1,3,5]triazinan-2,4,6-trione and all oxazines and pyrroles prepared in this work have been previously reported in the literature ( 2a , 2b , 2c , 2d , 2e , 2f , 3a , 3b , , 3c , , 3d , , 3e , , 3f , 4A , 5A,B 15 ), with the exception of the minor isomer 4B . Some additional spectroscopic data can be found in ref , together with some hints about products separation.…”

Section: Methodsmentioning

confidence: 67%

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Synthesis of Oxazines and N-Arylpyrroles by Reaction of Unfunctionalized Dienes with Nitroarenes and Carbon Monoxide, Catalyzed by Palladium−Phenanthroline Complexes

Ragaini¹,

Cenini²,

Brignoli³

et al. 2002

J. Org. Chem.

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The reaction between an unfunctionalized conjugated diene and a nitroarene under CO pressure and at 100 degrees C, catalyzed by [Pd(Phen)2][BF4]2 (Phen = 1,10-phenanthroline), affords the corresponding hetero-Diels-Alder adduct (oxazine) in up to 91% yields in one pot. If the reaction mixture is then heated to 200 degrees C, the oxazines are converted into the corresponding N-arylpyrroles in good yields. Pressures as low as 5 bar can be employed, and 0.08% catalyst is sufficient to effect the transformation. The reaction can be equally run by employing the nitroarene or the diene as limiting agent and works well for nitroarenes bearing either electron-withdrawing or mildly electron-donating substituents. A moderate steric hindrance on the nitroarene (o-methyl) is well tolerated, but 1,4-disubstituted-1,3-dienes are not suitable substrates.

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Section: Resultssupporting

confidence: 59%

Section: Methodsmentioning

confidence: 67%

Synthesis of Oxazines and N-Arylpyrroles by Reaction of Unfunctionalized Dienes with Nitroarenes and Carbon Monoxide, Catalyzed by Palladium−Phenanthroline Complexes

Ragaini¹,

Cenini²,

Brignoli³

et al. 2002

J. Org. Chem.

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“…The regioselectivity is independent of the electronic effects of substituents on 1,3-butadiene (3e). Interestingly, the addition of nitrosobenzene to a-myrcene exhibited a marked dependence on reaction temperature such that increasing the reaction temperature led to the reversed orientation of cycloaddition (4). In contrast, the cycloaddition of a nitrosobenzene having a strongly electron-withdrawing substituent, such as 4-(methoxy-carbonyl)nitrosobenzene, with isoprene proceeded with the opposite regioselectivity to yield a "para" adduct, eq.…”

Section: Introductionmentioning

confidence: 99%

Study of trichloronitrosomethane: regioselective cycloadditions of 2-substituted-1,3-butadienes

Lin¹,

Hsu²

1989

Can. J. Chem.

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CHENG-TUNG LIN and WEN-JEI HSU. Can. J. Chern. 67, 2153 (1989). The regioselectivity of cycloaddition reactions of trichloronitrosomethane (1) with 2-alkyl (R = Me, Et, i-Pr, t-Bu, CF3, Bz, and C1) and 2-aryl (Ar = Ph, 4-CH30Ph, 4-CH3Ph, 3-CH3Ph, and 4-ClPh) 1,3-butadienes is described. The orientation of cycloaddition is substituent dependent, producing 2,5-disubstituted (para) and 2,4-disubstituted (meta) 3,6-dihydro-1,2-oxazines from 2-alkyl-and 2-aryl-l,3-butadienes respectively. Increasing the bulk of the substituent from methyl to tert-butyl in 2-alkyl-l,3-butadienes increases the regioselectivity. Kinetic studies in various solvents indicate that plots of log k m / k H vs. Hammett u + values give straight lines with the p values lying between -0.60 and -0.91 for the reactions with 2-aryl-1,3-butadienes. A concerted reaction mechanism is proposed and the orientation preference is consistent with frontier molecular orbital predictions for 2-alkyl-l,3-butadienes. In the reactions with 2-aryl-l,3-butadienes, a transition state leading to a spin-paired diradical, which then converts by partial electron transfer to zwitterionic structure, is proposed. de la cycloaddition depend du substituant; i partir des 2-alkyl-et des 2-aryl-buta-l,3-diknes, on obtient respectivement des 3,6-dihydro-l,2-oxazines disubstitukes en 2,5 (para) et en 2,4 (mtta). Avec les 2-alkyl-buta-l,3-dibnes, une augmentation du volume du substituant (en allant du mkthyle au tert-butyle) provoque une augmentation de la rkgiosklectivitt. Des ttudes cinktiques dans divers solvants suggkrent que les courbes du log k m / k H vs. les valeurs u + de Hammett donnent des droites avec des valeurs de p variant de -0,60 A -0,91 pour les rkactions des 2-aryl-buta-l,3-dibnes. Pour les 2-alkyl-buta-l,3-diknes, on suggkre un mtcanisme rkactionnel concert6 et la prtfkrence de I'orientation est en accord avec les prkdictions des orbitales molkculaires frontikres. Dans les reactions des 2-aryl-buta-l,3-dibnes, on propose une ktat de transition conduisant A un diradical dont les spins sont pairks qui se transforme ensuite en une structure zwitterionique par un transfert partiel d'klectrons.

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ChemInform Abstract: UNTERSUCHUNGEN AN ISOPRENOIDEN 12. MITT. DIE 1,4‐CYCLOADDITIONSRK. VON NITROSOBENZOL MIT ISOPREN, CHLOROPREN UND MYRCEN

Sasaki¹,

Eguchi²,

Ishii³

et al. 1971

Chemischer Informationsdienst. Organische Chemie

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Reactions of isoprenoids. XII. 1,4-Cycloaddition reactions of nitrosobenzene with isoprene, chloroprene, and myrcene

Cited by 12 publications

References 1 publication

Synthesis of Oxazines and N-Arylpyrroles by Reaction of Unfunctionalized Dienes with Nitroarenes and Carbon Monoxide, Catalyzed by Palladium−Phenanthroline Complexes

Synthesis of Oxazines and N-Arylpyrroles by Reaction of Unfunctionalized Dienes with Nitroarenes and Carbon Monoxide, Catalyzed by Palladium−Phenanthroline Complexes

Study of trichloronitrosomethane: regioselective cycloadditions of 2-substituted-1,3-butadienes

ChemInform Abstract: UNTERSUCHUNGEN AN ISOPRENOIDEN 12. MITT. DIE 1,4‐CYCLOADDITIONSRK. VON NITROSOBENZOL MIT ISOPREN, CHLOROPREN UND MYRCEN

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