Photochemical Reactions of Metal-Complexed Olefins. II. Dimerization of Norbornene and Derivatives¹

Photocatalysis by transition-metal coordination compounds in homogeneous phase. Part II: Photochemical steps involving the organic substrate

“…~le dimerization of norbornene (NBN) is photocatalyzed by CuCI or CuBr [20] and by CuOTf [18]. Two isomers of the cyclobutane dimer were obtained, the Some derivatives of norbornene also undergo Cu(I) photocatalyzed reactions.…”

Computational and experimental studies into NMR characterization of [2+2] cycloaddition products of norbornene

“…The transition-metalcatalyzed dimerization of bicyclo[2.2.1]hept-2-ene (norbornene, nbe) was reported in 1965 [8,9]. Since then various metal complexes have been used as catalysts providing various isomers of pentacyclo [8.2.1.1 4,7 .0 2,9 .0 3,8 ]tetradecane, the [2+2] nbe dimer [10][11][12][13][14]. Two possible configurations (exo or endo) of two norbornane units and two different possibilities of connection (trans or cis) of the latter units to give the cyclobutane ring lead to six stereoisomeric structures of the [2+2] nbe dimer presented in Scheme 1.…”

“…Although the six isomers (exo-trans-exo (1), endo-trans-exo (2), endo-trans-endo (3), exo-cis-exo (4), endo-cis-exo (5), endo-cisendo (6)) of this nbe dimer can be formed, only three of them (1, 2 and 3), those with a trans connection of the norbornane units, have been synthesized and characterized by 1 H NMR. Isomer 1 was a major product of photochemical reaction of norbornene in the presence of copper(I) halides [8][9][10][11], while isomer 2 was obtained in a photosensitized reaction [8]. Isomer 3 was prepared by catalytic reduction of the [2+2] norbornadiene dimer with an endo-trans-endo configuration of the norbornene units [8].…”

Photoréactivité des complexes nitriles – cuivre (I) et (II). II. Système cyanure d'allyle – cuivre (I) et (II)

“…Notamment, l'aptitude du cuivre I 2 se fixer sur les doubles liaisons Cthylkniques a permis la synthkse photochimique de nombreux dCrivCs cyclobutaniques (1,2). L'emploi de CuCl comme catalyseur a Ct C dCcrit pour la dimkrisation de molecules a cycle tendu telles que le norbornkne ou le bicyclopentadikne (1). L'utilisation du triflate de cuivre CF3S03Cu a permis l'obtention de dCrivCs cyclobutaniques a partir de composCs 2 double liaison extracyclique (3):…”

“…Par excitation dans chacune des trois bandes de transfert de charge du complexe "B", on observe la destruction du complexe (rtapparition du signal du cuivre(I1) en rpe) et photoreduction du cuivre(I1) en cuivre (1).…”