16776-12-8Relevant academic research and scientific papers
Ni(cod)2/PCy3-catalyzed cross-coupling reactions of dihaloarenes with arylboronic acids
Dong, Cheng-Guo,Hu, Qiao-Sheng
supporting information, p. 2121 - 2125 (2012/11/07)
The Ni(0)-catalyzed cross-coupling reactions of dihaloarenes with one equivalent of arylboronic acids is described. The Ni(cod)2/PCy 3 was identified as the best catalyst system to achieve a double cross-coupling reaction, likely via an efficient preferential oxidative addition. Georg Thieme Verlag Stuttgart New York.
Reactions of 4,4-Diphenylcarbena-2,5-cyclohexadiene and Related Systems in Dimethyl Sulfoxide
Freeman, Peter K.,Tafesh, Ahmed M.,Clapp, Gary E.
, p. 782 - 789 (2007/10/02)
Thermal decomposition of the lithium salt of the tosylhydrazone of 4,4-diphenyl-2,5-cyclohexadienone (10) in dimethyl sulfoxide produces 4,4-diphenyl-2,5-cyclohexadienone, p-benzylbiphenyl, 3,4-diphenyltoluene, 6,6-diphenyl-1-methylene-2,4-cyclohexadiene, and o-terphenyl, while similar treatment of the lithium salt of the tosylhydrazone of 4,4-diphenylcyclohexenone (26) generates 4,4-diphenylcyclohexenone, 5,5-diphenyl-1,3-cyclohexadiene, 4,4-diphenyl-1-methylene-2-cyclohexene, and 6,6-diphenyl-1-methylene-2-cyclohexene.Thermolysis of the lithium salt of the tosylhydrazone of 4,4-diphenylcyclohexanone (32) in dimethyl sulfoxide yields 4,4-diphenylcyclohexene, 4,4-diphenylcyclohexanone, and 4,4-diphenyl-1-methylcyclohexanol.The kinetics of the thermal decomposition of tosylhydrazone lithium salts 10, 26, and 32 in dimethyl sulfoxide in the temperature range 90-125 deg C were analyzed by evaluating the rate constants for the two consecutive first-order steps.The second step, for parent salts 10, 26, and 32, decomposition of diazo compound to carbene, exhibited values for k2 (110 deg C) of 8.22, 197, and 363 h-1, ΔG(activ)s of 27.2 +/- 3.1, 24.8 +/- 3.1, 24.2 +/- 0.9 kcal mol-1, and Δ(activ)s of -10.7 +/- 5.7, -6.3 +/- 5.8, and -8.1 +/- 1.7 eu.The activation parameters for decomposition of the diazo compounds are interpreted in terms of an increasing dipole moment in the transition state relative to ground state.Product formation from carbene intermediate is viewed in terms of a competition of a singlet oxygen abstraction reaction with intersystem crossing to triplet.
THE REARRANGEMENT OF 4,4-DIPHENYLCYCLOHEXA-2,5-DIENYLIDENE
Freeman, Peter K.,Swenson, Karl E.
, p. 3737 - 3744 (2007/10/02)
Pyrolytic decomposition of the Li salt of the tosylhydrazone of 4,4-diphenyl-2,5-cyclohexadienone produces a mixture of biphenyl, o-terphenyl, p-terphenyl, methyl-o-terphenyl and the azine of 4,4-diphenyl-2,5-cyclohexadienone (13).Insight into the reaction pathway was provided by the pyrolytic decomposition of 2-deuterio tosylhydrazone 8a which generates o-terphenyl 10a and 10b in a ratio of 69:31.These results are interpreted in terms of the carbene rearrangements of Schemes 2, 3 and 5.
