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Norbornadiene
About: Norbornadiene is a research topic. Over the lifetime, 2389 publications have been published within this topic receiving 38603 citations.
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44 citations
TL;DR: In this article, the reduction of a series of Pd(II) complexes has been studied by electrochemistry and spectroscopy, yielding the first stable Pd (I)..pi.. radicals.
Abstract: The reduction of a series of Pd(II) complexes has been studied by electrochemistry and spectroscopy. Neutral Pd(I) radicals may be obtained from the reduction of (eta/sup 5/-C/sub 5/Ph/sub 5/)Pd(eta/sup 4/-diolefin) cations, where diolefin = 1,5-cyclotadiene, norbornadiene, or dibenzocyclooctatetraene. The one-electron processes are diffusion-controlled and highly reversible, yielding the first stable Pd(I) ..pi.. radicals. The dibenzocyclooctatetraene derivative is isolable. These complexes undergo radical reaction with water, chlorinated hydrocarbons, and peroxides to give ..pi..,sigma-Pd(II) complexes identical with those obtained by direct attack of nucleophiles on the starting Pd(II) cationic complexes. Reversible oxidation of (eta/sup 5/-C/sub 5/Ph/sub 5/)Pd(eta/sup 4/-diolefin) cations demonstrates the existence of formal Pd(III) complexes in these systems. The pentaphenylcyclopentadienyl ligand gives kinetic stabilization to both Pd(I) and Pd(III), compared to the unsubstituted cyclopentadienyl analogues.
44 citations
TL;DR: In this article, an enantioselective approach to carbanucleosides from Pauson-Khand (PK) adducts was disclosed, and the chiral cyclopentenone 1 was readily accessible in enantiomerically pure form via PK reaction of trimethylsilylacetylene and norbornadiene using N-benzyl-N-diphenylphosphino-tert-butyl-sulfinamide as a chiral P,S ligand.
44 citations
TL;DR: In this paper, four copper(I) complexes have been designed as photosensitizers for assisting the norbornadiene (NBD) → quadricyclene (Q) isomerization with the purpose of carrying out the reaction using visible light and achieving a high NBD/photocatalyst turnover.
Abstract: Four copper(I) complexes have been designed as photosensitizers for assisting the norbornadiene (NBD) → quadricyclene (Q) isomerization with the purpose of carrying out the reaction using visible light and achieving a high NBD/photocatalyst turnover. All complexes contain π-delocalized bidentate N⌒O monoanionic ligands. Their syntheses have been performed either by the metathesis reaction from CuCl or by reaction of the monoprotic ligands with Cu5Mes5 (Mes ≡ 2,4,6-Me3C6H2) in the presence of norbornadiene. The dinuclear complexes [Cu2L2(μ-NBD)], 3, [Cu2L‘2(μ-NBD)], 4, [Cu2L‘‘2(μ-NBD)], 5, and [Cu2L‘‘‘2(μ-NBD)], 6 [where L = 2-methyl-8-oxoquinolinato, L‘ = 2-methyl-5,7-dichloro-8-oxoquinolinato, L‘‘ = 4-oxoacridinato, and L‘‘‘ = 2-(2-oxo-3,5-di-tert-butyl phenyl)benzotriazole], have been isolated and characterized in the solid state, including the X-ray analysis on 3 and 6. All compounds show absorption in the visible spectrum, due to the presence of metal-to-ligand charge-transfer (MLCT) bands. Most were ...
44 citations
TL;DR: Both the allyl complex and the molybdate complex are the only metal-containing species observed by NMR in typical catalytic reactions and thus appear to be catalyst resting states.
Abstract: Spectroscopic and crystallographic studies were undertaken to gain insight into the mechanism of the highly regio- and enantioselective allylic aklylation reaction catalyzed by molybdenum. The chiral ligand (L*) consisting of the mixed benzamide/picolinamide of (S,S,)-trans-1,2-diaminocyclohexane reacts with a typical Mo precatalyst, (norbornadiene)Mo(CO)4, to give a neutral complex L*Mo(CO)4 in which the ligand binds to the metal in a bidentate fashion through the pyridine and adjacent amide group. Reaction of this complex with the methyl carbonate of cinnamyl alcohol gives the corresponding π-allyl complex L*(CO)2Mo(η3-CH2CH−CHPh). NMR and X-ray crystallographic characterization of this complex reveal the ligand binds in a facially capping tridentate fashion via the pyridine nitrogen, the nitrogen of the adjacent amide group, which has now been deprotonated, and the carbonyl oxygen of the remote amide. Surprisingly, the face of the allyl group open to attack with nucleophiles is that which would lead to...
44 citations