6093-01-2Relevant academic research and scientific papers
Triplet halocarbene chemistry: P-nitrophenylchlorocarbene and p-nitrophenylbromocarbene
Moss, Robert A.,Lu, Zhifeng,Sauers, Ronald R.
body text, p. 5940 - 5942 (2010/11/21)
Reactions of p-nitrophenylchlorocarbene with cumene and of p-nitrophenylbromocarbene with toluene afford C-H abstraction-recombination products that suggest the involvement of triplet arylhalocarbenes.
Modern friedel-crafts chemistry. Part 25. Friedel-crafts alkylation of benzene with 3-chloro-2-(chloromethyl)-1-propene
Khalaf, Ali A.,Albar, Hassan A.,Bahaffi, Saleh O.
, p. 895 - 898 (2008/04/18)
The major alkylation products of benzene with 3-chloro-(2-chloromethyl)-1- propene (1) and H2SO4 catalyst were 1,1-di(chloromethyl) ethylbenzene (2), three simple isomeric dimers of 1 (structures 5a,b,c) and five mixed isomeric dimers resulting from a combination of 4 with 6 (molecular formula 7). With AlCl3 or K10-montmorillonite clay catalyst, however, the major alkylation products were cis- and/or trans-2-methyl-1-phenylindan (11) and 1-chloro-2-methyl-3,3-diphenylpropane (14) proving that the latter two catalysts have dual Lewis-Broenested catalytic activities.
Remarkably stable iron porphyrins bearing nonheteroatom-stabilized carbene or (alkoxycarbonyl)carbenes: Isolation, X-ray crystal structures, and carbon atom transfer reactions with hydrocarbons
Li, Yan,Huang, Jie-Sheng,Zhou, Zhong-Yuan,Che, Chi-Ming,You, Xiao-Zeng
, p. 13185 - 13193 (2007/10/03)
Reactions of [Fe(TPFPP)] (TPFPP = meso-tetrakis(pentafluorophenyl)porphyrinato dianion) with diazo compounds N2C(Ph)R (R = Ph, CO2Et, CO2CH2CH=CH2) afforded [Fe(TPFPP)(C(Ph)R)] (R = Ph (1), CO2Et (2), CO2CH2CH=CH2 (3)) in 65-70% yields. Treatment of 1 with N-methylimidazole (Melm) gave the adduct [Fe(TPFPP)(CPh2)(Melm)] (4) in 65% yield. These new iron porphyrin carbene complexes were characterized by NMR and UV-vis spectroscopy, mass spectrometry, and elemental analyses. X-ray crystal structure determinations of 1·0.5C6H6·0.5CH2Cl2 and 4 reveal Fe=CPh2 bond lengths of 1.767(3) (1) and 1.827(5) A (4), together with large ruffling distortions of the TPFPP macrocycle. Complexes 2 and 4 are reactive toward styrene, affording the corresponding cyclopropanes in 82 and 53% yields, respectively. Complex 1 is an active catalyst for both intermolecular cyclopropanation of styrenes with ethyl diazoacetate and intramolecular cyclopropanation of allylic diazoacetates. Reactions of 2 and 4 with cyclohexene or cumene produced allylic or benzylic C-H insertion products in up to 83% yield.
PHOTOSENSITIZED (ELECTRON TRANSFER) CARBON-CARBON BOND CLEAVAGE OF RADICAL CATIONS; THE DIPHENYLMETHYL SYSTEM
Okamoto, Akio,Snow, Miles S.,Arnold, Donald R.
, p. 6175 - 6187 (2007/10/02)
The photosensitized (electron transfer) reaction of methyl 2,2-diphenylethyl ether (1), 1,1,2,2-tetraphenylethane (5), 2-methyl-1,1,2-triphenylpropane (6), and 2-methoxy-2-diphenylmethylnorbornane (11 endo and exo) with 1,4-dicyanobenzene (4) in acetonitrile-methanol leads to products indicating cleavage of an intermediate radical cation to give the diphenylmethyl radical and a carbocation.The diphenylmethyl radical is then reduced by the radical anion of the photosensitizer and protonated to yield diphenylmethane.The carbocation fragment reacts with methanol to yield ether and/or acetals.The effect of temperature on the efficiency of cleavage of 5 and 6 has been analyzed.The increase in efficiency observed at higher temperatures reflects an activation energy for the cleavage of the radical cations.In cases where no cleavage is observed, the activation energy for cleavage may be so high that back electron transfer from the radical anion of the photosensitizer is the dominant reaction.The C-C bond dissociation energies of the radical cations of 5 and 6 were estimated by analysis of the thermochemical cycle using the bond dissociation energies and the oxidation potentials of the neutral molecules and the oxidation potential of the diphenylmethyl and cumyl radicals.The direction of cleavage of the radical cation is explained in terms of the relative oxidation potentials of the two possible radicals.
