Mechanistic Study of the Ru(H)2(CO)(PPh3)3-Catalyzed Addition of C–H Bonds in Aromatic Esters to Olefins

Abstract

The reaction mechanism of the Ru(H)2(CO)(PPh3)3-catalyzed addition of C–H bonds in aromatic esters to olefins was studied by means of deuterium-labeling experiments and measurement of the 13C kinetic isotope effect. The deuterium-labeling experiment revealed a rapid equilibrium among the intermediates prior to the reductive elimination, and the 13C NMR kinetic isotope effect indicated that C–C bond formation is the rate-determining step in this reaction.

Catalytic Methods for CH Bond Functionalization: Application in Organic Synthesis

“…The studies of 13 C KIE for this coupling reaction also provide support that the reductive elimination step is rate-determining. [28] Thus, Murai×s experimental results are consistent with Morokuma×s theoretical calculation. [27] 9 Brookhart found another important phenomenon for the chelation-assisted C À H/olefin couplings.…”

“…(28). [57] Miura found that the reaction of phenylboronic acid with excess amounts of norbornene using [RhCl(cod)] 2 /DPPP [DPPP 1,2-28 REVIEWS Fumitoshi Kakiuchi, Naoto Chatani bis(diphenylphophino)propane] as catalyst results in multiple substitution with norbornene on aromatics in high yield (Scheme 3).…”

Organometallic C—H Bond Activation: An Introduction

“…In accord with this result, coupling reactions showed a significant 13 C KIE (for the ortho carbon) implicating C-C coupling as the rate-determining step (119). In an unusual example of chemoselectivity in this system, only aryl esters with electron-withdrawing groups undergo coupling (120) (whereas aryl ketones tolerate electron-withdrawing and -donating groups).…”

Catalytic Addition of C – H Bonds to C – C Multiple Bonds

“…The carbonyl group in aromatic esters [33,34], aldehydes [35], and amides [36] can also function as a directing group. In the studies of alkylations of these aromatic compounds, several important features of the catalytic alkylation of C -H bonds have been revealed.…”

“…In the studies of alkylations of these aromatic compounds, several important features of the catalytic alkylation of C -H bonds have been revealed. Murai and coworkers investigated the reaction mechanism by means of deuterium-labeling experiments and the 13 C kinetic isotope effect at natural abundance [34]. They revealed that there is a rapid equilibrium between the intermediates prior to the C -C bond formation step, i.e., a reductive elimination step, and that the C -C bond formation is rate-determining in the catalytic cycle (Scheme 7).…”