22557-45-5Relevant academic research and scientific papers
Alder-ene reaction of aryne with olefins
Chen, Zhao,Liang, Jinhua,Yin, Jun,Yu, Guang-Ao,Liu, Sheng Hua
supporting information, p. 5785 - 5787 (2013/10/01)
A novel intermolecular Alder-ene reaction based on aryne and olefins was developed. We performed this transformation under mild conditions such as at room temperature, and this reaction displayed high selectivity and good yields only in the presence of CsF. Hence, the intermolecular Alder-ene reaction of aryne with olefins provides an effective route to synthesize derivatives of olefins.
Methyl Group Migration in the Reactions of Alkynyltrialkylborates
Pelter, Andrew,Drake, Robert A.
, p. 4181 - 4184 (2007/10/02)
It is shown that the methyl group cannot be used as a cheap, non-migrating group in the reactions of alkynyltrialkylborates with electrophiles.However, trimethylborane can be used as a methylboronating agent for alkynes, given the right choice of solvent, and this may be of use in terpene synthesis.
Solvolysis of 2-Aryl-3,3-dimethyl-2-butyl p-Nitrobenzoates. β-Deuterium Kinetic Isotope Effects and the Linear Free Energy Relationships
Liu, Kwang-Ting,Kuo, Mann-Yan
, p. 3523 - 3530 (2007/10/02)
Solvolysis of 2-aryl-3,3-dimethyl-2-butyl p-nitrobenzoates (4a-4d) and the 1,1,1-trideuterio derivatives (5a,5b,5c) in HFIP exhibited a high kinetic isotope effect, k(CH3)/k(CD3) = 1.90 at 60 deg C for the deactivating substrates 4c vs 5c.This effect decreased significantly with increasing electron releasing of the substituent on the aryl ring.Hammett-Brown treatment of the rate data for 4 yielded excellent linear relationships (r = 0.999) with ρ+ = -3.48.It is evident that the contribution of the α-methyl group to the stabilization of the cationic transition state is not constant.The approximation in the linear free energy relationship is discussed.
THERMISCHER ZERFALL VON Β-PHENYL UND Β,Β-DIPHENYL-NITROALKANEN
Fritzsche, Katharina,Beckhaus, Hans-Dieter,Ruechardt, Christoph
, p. 2805 - 2808 (2007/10/02)
Elimination of nitrous acid is the exclusive reaction path for the thermal decomposition of the nitroalkanes 1, 2 and 5.Homolytic CC-cleavage cannot compete.A concerted β-elimination is the favoured mechanism.
The Photoaddition of Ethylenic Hydrocarbons to Benzene
Bryce-Smith, Derek,Foulger, Brian,Forrester, John,Gilbert, Andrew,Orger, Brian H.,et al.
, p. 55 - 71 (2007/10/02)
The photoreactions of a range of acyclic and cyclic ethylenic hydrocarbons with benzene are described.The processes which occur depend on the ethylene, and in particular on its ionisation potential relative to that benzene, but in general, meta-cycloadditions occur in every case and often predominate. ortho-Cycloaddition tends mostly to occur with the ethylenes of lowest ionisation potential relative to that of benzene, and para-cycloaddition occurs with cyclobutene to a significant extent, but not with cyclopropene or cyclopentene.Acyclic ethylenes containing the group Me2C= also undergo ene-type acyclic para-addition to benzene to give cyclohexa-1,4-dienes.The ortho-, meta-, and para-cycloadditions are stereospecific with respect to the ethylene, but the ene-addition is non-stereospecific.The former are mostly insensitive to solvent polarity, the exception being ortho-cycloaddition of 2,3-dimethylbut-2-ene which is definitely promoted by polar solvents.The ene-addition of 2,3-dimethylbut-2-ene was promoted by methanol but not by acetonitrile: the use of CH3OD led non-stereospecifically to incorporation of deuterium in the 4-position of the adduct.Cyclohexene was anomalous in giving mainly a mixture of three cyclobutane dimers, with only minor proportions of the endo and exo, meta-adducts and possibly a trace of the para-cycloadduct.The photocyclisation of benzene to give a range of essentially saturated polymers up to ca. (C6H6)24 can be initiated by traces of cis-cyclo-octene.All the products, with the exception of the cyclobutane dimers from cyclohexene, are considered to be formed via S1 benzene, although T1 benzene-sensitised cis-trans isomerisation of the ethylenes also slowly occurs: Thus prolonged irradiation of cis-cyclo-octene and benzene leads eventually to the formation of trans-cyclo-octene and the corresponding cycloadducts.The mechanisms of these processes are discussed with reference to orbital symmetry considerations, and the observed effects of polar solvents and proton donors.Only the meta-cycloadditions appear to occur by concerted processes involving either initial meta-bonding in S1 benzene or initial meta-cycloaddition of the ethylene to S1 benzene.The ortho- and para-cycloadditions are formally forbidden as concerted processes from S1 benzene plus S0 ethylene, and these are considered to involve intermediates having a degree of dipolar character.
