131792-84-2Relevant academic research and scientific papers
Pd-Catalyzed Coupling of N-Tosylhydrazones with Benzylic Phosphates: Toward the Synthesis of Di- or Tri-Substituted Alkenes
Zhang, Kena,Provot, Olivier,Alami, Mouad,Tran, Christine,Hamze, Abdallah
, p. 1249 - 1261 (2022/02/07)
This study shows that various di- and tri-substituted alkenes with high chemoselectivity were obtained in good to high yields by coupling N-tosylhydrazones (NTHs) with benzylic phosphates as electrophilic partners. The obtained new catalytic system consis
Reactions of N-acylaziridines with sodium metal and sodium naphthalenide. Elimination of olefines
Lin, Pen-Yuan,Bellos, Konstantinos,Werry, Juergen,Assithianakis, Petros,Weiss, Rainer,Mall, Thomas,Bentz, Gunther,Stamm, Helmut
, p. 270 - 278 (2007/10/03)
Reactions of N-acylaziridines 1a-g (N-benzoyl except 1d) with sodium or naphthalenide N.- in THF provide a variety of products that usually arise via the aziridino ketyls 2. Homolytic ring opening of 2 generates the amidatoalkyl radicals 3. Only with a very short reaction time were small amounts of benzil or benzoylnaphthalenes obtained indicating a reversible trapping of 2 by dimerization or coupling with N.-. Homolysis of 2 produced always the more stable 3 apart from reactions of monomethylaziridines 1c,d where the primary radical i-3c,d is kinetically favoured. The amides R1CONHCHR4CHR2R3 (9, isopropylamides i-9c,d from 1c,d) were usually the main products. 9 arise from 3 either by H atom abstraction from THF (probably in sodium metal runs) or by reduction of 3 to carbanions 5 that abstract a proton from THF (N.- runs). Addition of 5a (R2-4 = H) to 1a gives finally the ketone 8a. Self reaction of primary radical 3a is dimerization. Self reaction of tertiary or secondary radicals is disproportionation when an allylamide arises. This isomerizes to an enamide unless it is conjugated. R2R3C=CHR4 and R1CONH2 arise (probably) always. The mechanism, possibly a cyclic process of anion 6, is not clear. Johann Ambrosius Barth 1996.
Radical-Stabilization-Energy - the MMEVBH Force Field
Roth, Wolfgang R.,Staemmler, Volker,Neumann, Martin,Schmuck, Carsten
, p. 1061 - 1118 (2007/10/02)
Making use of the VB method of Malrieu et al. a force field has been developed, which allows to calculate heats of formation of hydrocarbons (conjugated and non-conjugated olefins, radicals and diradicals) with high accuracy.With this method radical stabilization energies (RSE) for a great number of delocalized radicals are calculated and compared with experimental values, derived from shock-tube measurements of dissociation energies or from rotational barriers of substituted olefins.A detailed analysis of the RSE with respect to structure, substituents, strain, and aromaticity is presented. - Key Words: Resonance energy / Heats of formation / Single pulse shock tube / Intrisic rotational barrier
Palladium-catalyzed cross-coupling of aryl and alkenyl boronic acids with alkenes via oxidative addition of a carbon-boron bond to palladium(0)
Cho, Chan Sik,Uemura, Sakae
, p. 85 - 92 (2007/10/02)
Arylboronic acids react with alkenes in acetic acid at 25 deg C in the presence of a catalytic amount of palladium(II) acetate together with sodium acetate to give the corresponding aryl-substituted alkenes in high yields.Alkenylboronic acids react with alkenes under similar conditions to give the corresponding conjugated dienes stereospecifically, but the product yields are lower, compared with those from arylboronic acids.Similar treatment of sodium tetraphenylborate (NaBPh4) with alkenes also affords the corresponding phenylated alkenes in high yields together with biphenyl and benzene as side products.Oxidative addition of a carbon-boron bond to palladium(0), formed in situ, to give an organopalladium(II) species is assumed to be the key step of these cross-coupling reactions. Key words: Boronic acid; Aryl; Alkenyl; Alkene; Palladium; Oxidative addition
NiCl2(dppe)-Catalyzed Geminal Dialkylation of Dithioacetals and Trimethylation of Ortho Thioesters
Tzeng, Yih-Ling,Yang, Ping-Fan,Mei, Nai-Wen,Yuan, Tien-Min,Yu, Chun-Chi,Luh, Tien-Yau
, p. 5289 - 5293 (2007/10/02)
NiCl2(dppe)-catalyzed cross-coupling of cinnamaldehyde dithioacetals gave the corresponding geminal dimethylation products in excellent yields.Allylic ortho thioesters afforded regioselectively the corresponding trimethylation products.The reaction may occur via an 18-electron ?-allyl intermediate, which undergoes facile reductive elimination to afford the geminal dimethylation product.Benzylic dithioacetals having an ortho amino group gave 2-isopropylanilines exclusively.The reaction of benzylic dithioacetals with EtMgBr under the same conditions yielded geminal diethylation products.
Rearrangement of 1,3-Diradicals. Arylcyclopropane Photochemistry
Zimmerman, Howard E.,Heydinger, Jenifer A.
, p. 1747 - 1758 (2007/10/02)
The photochemistry of a series of aryl-substituted cyclopropanes was investigated as part of our continuing investigations of these systems.The literature held a puzzling discrepancy in which several similar reactants exhibited differing photochemistry.A series of 3-aryl-1,1,2,2-tetramethylcyclopropanes was found to rearrange photochemically to give primarily two types of products, the anticipated 4-aryl-2,3,3-trimethyl-1-butenes and, additionally, 1-aryl-2,3,3-trimethyl-1-butenes.The latter arise from regioselective methyl migration of intermediate singlet 1,3-diradicals.Also, the usual Griffin carbene fragmentation was encountered as a minor pathway.Biphenylyl-, p-cyanophenyl-, and p-anisyl-substituted cyclopropanes were studied.Also, the photochemistry of 3-phenyl-1,1,2,2-tetramethylcyclopropane was reinvestigated and found to conform to the general pattern of reactivity.Throughout, it was the singlet excited states responsible for the observed reactivity, and the triplet counterparts were found to be unreactive.In addition, the photochemistry of 3-biphenylyl-2,2-dimethyl-1,1-diphenylcyclopropane was studied.Again, the triplet was unreactive.The singlet gave rise to 4-biphenylyl-2-methyl-3,3-diphenyl-1-butene exclusively.The differing behavior of the various arylcyclopropanes is discussed from a mechanistic viewpoint.In the case of the 3-aryl-1,1,2,2-tetramethylcyclopropanes, the regioselectivity of the 1,3-diradical intermediate favors migration toward the less delocalized odd-electron center.This selectivity is understood on a quantum mechanical basis.Finally, quantum yields are reported.
