10468-65-2Relevant academic research and scientific papers
Palladium-catalyzed arylation of α,α-disubstituted arylmethanols via cleavage of a C-C or a C-H bond to give biaryls
Terao, Yoshito,Wakui, Hiroyuki,Nomoto, Michiyo,Satoh, Tetsuya,Miura, Masahiro,Nomura, Masakatsu
, p. 5236 - 5243 (2007/10/03)
The palladium-catalyzed arylation of α,α-disubstituted arylmethanols with aryl halides proceeds not only via C-H bond cleavage at the ortho-position, but also via cleavage of the sp2-sp3 C-C bond with the liberation of ketones (β-carbon elimination) to give the corresponding biaryls. Both reactions appear to occur through common arylpalladium(II) alcoholate intermediates. The results of systematic studies with respect to which C-C or C-H bond is preferentially cleaved in the arylation are reported. Among the important findings is the selective elimination of ortho-substituted aryl groups even from aryl(diphenyl)methanols due to steric reasons. Thus, various biaryls having ortho-substituents can be produced efficiently by treatment of the corresponding aryl(diphenyl or dimethyl)methanols with aryl bromides and chlorides.
Photocyclization of 2-vinylbiphenyls: stereochemistry of the triplet state cyclization
Lapouyade, Rene,Manigand, Claude,Nourmamode, Aziz
, p. 2192 - 2196 (2007/10/02)
The photochemistry of the five- to eight-membered ring cotaining 2-cycloalkenyl biphenyls was examined under direct and sensitized irradiation.From the singlet excited state only trans 9,10-cycloalkyl-9,10-dihydrophenanthrenes were obtained.From the triplet state the trans isomer was exclusively formed from 2-cyclopentenyl and 2-cyclohexenyl biphenyls while the cis isomer also appeared with 2- cycloheptenyl and 2-cyclooctenyl biphenyls.We propose that the cis isomers resulted from the cyclization of the perpendicular triplet of cycloheptenyl biphenyl and from the perpendicular and trans triplet of cyclooctenyl biphenyl.Whereas the photocyclization of 2-vinylbiphenyls was regarded as a singlet-state reaction, the quantum yields of reaction of 2-cycloalkenyl biphenyls, from both singlet and triplet states, were high (ΦS=0.20-0.26; ΦT=0.15-0.46).
