Solid Superacid Catalyzed Organic Synthesis. 6. Perfluorinated Resinsulfonic Acid (Nafion-H) Catalyzed Ring Closure Reaction of 2,2'-Dihydroxybiphenyls. A Preparative Route to Dibenzofurans
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Yamato, Takehiko,Hideshima, Chieko,Prakash, G. K. Surya,Olah, George A.
p. 3192 - 3194
(2007/10/02)
Reactions of Alkyl-lithium Compounds with Aryl Halides
Reation of methyl-lithium with tribromophenols and with other aryl polyhalides leads directly to bi- and tri-aryl products. para-Substituents (Y) of 2,6-dibromo-4-Y-phenols promote arylation of substrates by their own lithiation products as Y becomes more electron-withdrawing.An aryne epoxide is not an intermediate in these reactions. 2,4,6-Tribromo-Z-benzenes react to form coupling products when Z can co-ordinate to an introduced ortho-lithium atom or when Z can be directly lithiated.Dimeric aggregation of the organolithium intermediates occurs so as to favor coupling to halogenated substrates.Both polar (ionic) and free-radical pathways are involved.
Huddle, Penelope A.,Perold, Guido W.
p. 2617 - 2625
(2007/10/02)
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