Ring-opening isomerization of methylenecyclopropanes catalyzed by hydridorhodium(I) complexes

β-Alkyl Elimination: Fundamental Principles and Some Applications

“…However, Osakada and co-workers demonstrate that Rh I –H and Ir I –H species mediate C–C bond cleavage by β-alkyl elimination (Scheme ). − Treating 2-phenyl-1-methylenecyclopropane ( 128 ) with (PPh 3 ) 3 (CO)­Rh­(H) ( 129 ) produces 2-phenyl-1,3-butadiene ( 130 ) as the exclusive product. For this reaction, the C–C bond cleavage occurs selectively at the least sterically hindered site, followed by rapid β-H elimination.…”

Preparation, Structures, and Thermal Reactivity of Alkoxycarbonyl(cyano)palladium(II) Complexes trans-Pd(COOR)(CN)(PPh3)2 (R = Me, Et, nPr, iPr, nBu, tBu, and Bn) as Intermediates of the Palladium-Catalyzed Cyanoesterification of Norbornene Derivatives

“…The activation of carbon−carbon σ-bonds promoted by transition metal complexes has been one of the most prominent challenges in both synthetic organic and organometallic chemistry. − For instance, transition metal hydrido complexes can affect C−C bond-breaking or -forming processes for simple dienes to afford branched dienes . Owing to their high ring strain, small-membered ring molecules are easily converted into their ring-opened products via C−C bond cleavage mediated by transition metal complexes. , However, in most cases, the carbon−carbon σ-bond cleavage reaction is limited to the ring-opening, intramolecular rearrangement reactions or formation of the stable metal complexes as the intermediates . On the other hand, although the double functionalization of unsaturated organic molecules via C−C σ-bond cleavage and the subsequent addition to unstrained molecules have been reported, much less attention has been paid to the mechanism of the catalytic reactions.…”

Synthesis and Characterization of Post-β-Carbon-Elimination Organopalladium Complexes

“…8,10,11 Owing to its importance in synthetic chemistry, fundamental organometallic studies of b-carbon elimination using both early and late transition metals have been pursued, with representative examples yielding well-defined products summarized in Scheme 1B. [12][13][14][15][16][17][18][19][20] The Flood group observed cyclobutane ring-opening b-alkyl elimination of organoplatinum complexes in the solution state by NMR. 12 In 1995, Anderson and Bergman demonstrated reversible b-methyl elimination and migratory insertion of a ruthenacyclobutane.…”

“…15 In 2005, Osakada and co-workers observed a post b-alkyl elimination organorhodium complex by NMR at low temperature upon reaction between methylenecyclopropanes and a hydridorhodium(I) complex. 17 More recently, Hartwig group demonstrated series of b-aryl elimination of rhodium(I) alkoxo and iminyl complexes. 19,20 Considering its relevance in modern cross-coupling, 9a,21 alkene functionalization, 9d,22,23 C-H activation, [24][25][26] and polymerization methodology, 27,29 b-elimination from alkylpalladium species has special relevance and importance in catalysis.…”