English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Open

Presents the pdf analysis as premium feature

PDF Analysis

Insights

Presents the summarisation as premium feature

Summarisation

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Metal-catalyzed decarboxylative coupling reactions of esters offer new opportunities for formation of C–C bonds with CO 2  as the only coproduct. Here I provide an overview of: key solution phase literature; thermochemical considerations for decarboxylation of esters and thermolysis of esters in the absence of a metal catalyst. Results from my laboratory on the use of multistage ion trap mass spectrometry experiments and DFT calculations to probe the gas-phase metal catalyzed decarboxylative cross-coupling reactions of allyl acetate and related esters are then reviewed. These studies have explored the role of the metal carboxylate complex in the gas phase decarboxylative coupling of allyl acetate proceeding via a simple two-step catalytic cycle. In Step 1, an organometallic ion, [CH 3 ML] +/–  (where M is a group 10 or 11 metal and L is an auxillary ligand), is allowed to undergo ion-molecule reactions with allyl acetate to generate 1-butene and the metal acetate ion, [CH 3 CO 2 ML] +/– . In Step 2, the metal acetate ion is subjected to collision-induced dissociation to reform the organometallic ion and thereby close the catalytic cycle. DFT calculations have been used to explore the mechanisms of these reactions. The organometallic ions [CH 3 CuCH 3 ] – , [CH 3 Cu 2 ] + , [CH 3 AgCu] +  and [CH 3 M(phen)] +  (where M = Ni, Pd and Pt) all undergo C–C bond coupling reactions with allyl acetate (Step 1), although the reaction efficiencies and product branching ratios are highly dependant on the nature of the metal complex. For example, [CH 3 Ag 2 ] +  does not undergo C–C bond coupling. Using DFT calculations, a diverse range of mechanisms have been explored for these C–C bond-coupling reactions including: oxidative-addition, followed by reductive elimination; insertion reactions and S N 2-like reactions. Which of these mechanisms operate is dependant on the nature of the metal complex. A wide range of organometallic ions can be formed via decarboxylation (Step 2) although these reactions can be in competition with other fragmentation channels. DFT calculations have located different types of transition states for the formation of [CH 3 CuCH 3 ] – , [CH 3 Cu 2 ] + , [CH 3 AgCu] +  and [CH 3 M(phen)] +  (where M = Ni, Pd and Pt). Of the catalysts studied to date, [CH 3 Cu 2 ] +  and [CH 3 Pd(phen)] +  are best at promoting C–C bond formation (Step 1) as well as being regenerated (Step 2). Preliminary results on the reactions of [C 6 H 5 M(phen)] +  (M = Ni and Pd) with C 6 H 5 CO 2 CH 2 CH=CH 2  and C 6 H 5 CO 2 CH 2 C 6 H 5  are described.

Gas-phase studies of metal catalyzed decarboxylative cross-coupling reactions of esters