85267-80-7Relevant academic research and scientific papers
Synthesis of Alkenylboronates from N-Tosylhydrazones through Palladium-Catalyzed Carbene Migratory Insertion
Chang, Taiwei,Huo, Jingfeng,Lei, Ming,Ping, Yifan,Wang, Jianbo,Wang, Qianyue,Wang, Rui
, p. 9769 - 9780 (2021/07/19)
The palladium-catalyzed oxidative borylation reaction of N-tosylhydrazones has been developed. The reaction features mild conditions, broad substrate scope, and good functional group tolerance. It thus represents a highly efficient and practical method for the synthesis of di-, tri-, and tetrasubstituted alkenylboronates from readily available N-tosylhydrazones. One-pot Suzuki coupling and other transformations highlight the synthetic utility of the approach. DFT calculations have revealed that palladium-carbene formation and subsequent boryl migratory insertion are the key steps in the catalytic cycle. The high stereoselectivity observed in the formation of trisubstituted alkenylboronates has been explained by distortion-interaction analysis and NBO analysis.
Thermolysis of trans-3-chloro-4,4,5-trimethyl-3,5-diphenyl-4,5-dihydro-3H- pyrazole
Desalegn, Nebiyou,Vasquez, Pedro C.,Franklin, Paul J.,Kennedy, G. Davon,Baumstark
, p. 375 - 378 (2007/10/03)
The thermal decomposition of trans-3-chloro-4,4,5-trimethyl-2,5-diphenyl-4, 5-dihydro-3H-pyrazole (1) produced 1,1,3-trimethyl-2-phenylindene (2) in excellent yield. A kinetic analysis showed that the reaction involved isolable diene intermediate(s) and yielded activation parameters for thermolysis of 1 of: ΔH?= 32.9 kcal/mole; ΔS?= -2.4 eu; ΔG?= 33.9 kcal/mole; k1, (180°C) - 1.3×10-3s -1.
Pd(0)-catalysed formation of diarylated dienes from propargyl carbonates and organoboron and organotin(IV) reagents
Boehmer, Jutta,Grigg, Ronald
, p. 13463 - 13470 (2007/10/03)
The 1,1-dimethylbutyne-1,4-diol derivative 1 reacts with 2 mol. equiv. of organoboron (NaBPh4 arylboronic acids) and organotin(IV) reagents to give 1,1-dimethyl-2,3-disubstituted butadienes in good yield via allenylpalladium(II) and vinylidene-π-allylpalladium(II) intermediates. Unsubstituted esters 6 and butyne dicarbonate 7 lead to symmetrical dienes 8.
Studies Dealing with the Cycloreversion Reactions of Phenyl-Substituted 2,3-Diazabicyclohex-2-enes
Padwa, Albert,Kumagai, Tsutomu,Tohidi, Mahrokh
, p. 1834 - 1840 (2007/10/02)
A study of the reactivity of 2-diazopropane with a series of diphenyl-substituted cyclopropenes has been carried out.The cycloadditions afford 1,5-diphenyl-2,3-diazabicyclohex-2-enes in high yield.Thermolysis of the diazabicyclohexene system for extended periods of time afforded a mixture of 1,3-dienes as well as a substituted bicyclobutane.By studying the distribution of products as a function of time it was possible to show that the 2,3-diazabicyclohexene system first rearranges to an isomeric 1,2-diazabicyclohex-2-ene.This reaction was attributed to an initial cycloreversion to produce a diazoalkene.Attack of the terminal nitrogen atom of the initially generated diazo group onto the neighboring double bond affords the bicyclic aziridine system.Reasonable mechanistic options for the 1,1-cycloaddition include a concerted pathway or a stepwise process.On further heating the 1,2-diazabicyclohexene ring regenerates the allyl-substituted diazoalkane.Loss of nitrogen produces a carbene which undergoes a hydrogen or vinyl shift to give the observed dienes.The formation of the bicyclobutane ring can be viewed in terms of a process involving initial C-N bond cleavage of the 2,3-diazabicyclohexene to yield a diazenyl radical followed by nitrogen loss and radical coupling.In contrast to the thermal results, direct irradiation of the 2,3-diazabicyclohexene results in a cycloreversion to give a 3,4-diaza-substituted 1,3,5-hexatriene derivative.The results obtained indicate that the total mechanistic picture for the thermal and photochemical decomposition of bicyclic pyrazolines can be changed dramatically by the presence of phenyl substituents.
