Gas‐phase studies of copper(I)‐mediated CO₂ extrusion followed by insertion of the heterocumulenes CS₂ or phenylisocyanate

Abstract

The gas-phase extrusion-insertion reactions of the copper complex [bathophenanthroline (Bphen)Cu I (O 2 CC 6 H 5 )] 2− , generated via electrospray ionization, was studied in a linear ion trap mass spectrometer with the combination of collisioninduced dissociation (CID) and ion-molecule reaction (IMR) events. Multistage mass spectrometry (MS n ) experiments and density functional theory (DFT) demonstrated that extrusion of carbon dioxide from [(Bphen)Cu(O 2 CC 6 H 5 )] 2− (CID) gives the organometallic intermediate [(Bphen)Cu(C 6 H 5 )] 2− , which subsequently reacts with carbon disulfide (IMR) via insertion to yield [(Bphen)Cu (SC(S)C 6 H 5 )] 2− . The fragmentation of the product ion resulted in the formation of [Bphen] 2− , [(Bphen)Cu] − and C 6 H 5 CS 2 −under CID conditions. The formation of the latter two charge separation products thus provides evidence of C-C bond formation in the IMR step. Although analogous studies with isocyanate, which is isoelectronic with CS 2 , showed a poor reactivity in the gas phase, the mechanistic understanding obtained from these model studies encourages future development of a solution phase protocol for the synthesis of amides from carboxylic acids and isocyanates mediated by copper(I) complexes.

Mechanistic Study of Cu-Catalyzed Addition Reaction of lsocyanates

“…O'Hair 等 [13] 通过理论计算研究探索了铜催化异氰酸酯 氢芳基化的反应机理. 他们发现, 当芳基铜(I)物种生成 后, 异氰酸酯的碳氧双键插入活化能仅为 15.4 kcal/mol, 远远低于碳氮双键插入的活化能.…”

Palladium-mediated CO2 extrusion followed by insertion of ketenes: translating mechanistic studies to develop a one-pot method for the synthesis of ketones

“…Our initial report on transformation of the anionic copper acetate complex [(CH 3 )Cu(O 2 CCH 3 )] − to the anionic copper(I) dithioacetate complex [(CH 3 )Cu(S 2 CCH 3 )] − [17] convinced us that guided by mechanistic studies, these extrusion-insertion (ExIn) reactions could potentially be harnessed for one-pot organic synthetic methods for a wide range of new species including thioamides, amidines, amides, alkenes and ketones (Eqn 1, Scheme 1a). [18][19][20][21][22][23][24] In potential competition with the desired products is the protodecarboxylation side reaction (Eqn 2, Scheme 1a and Cycle B, Scheme 1b). [25,26] Fortunately, comprehensive investigations by Kozlowski's group into the scope of the palladium-catalysed protodecarboxylation side reaction identified potential solvent and additives that suppress this reaction, [25] which provided a valuable starting point in our solution-phase investigations.…”

Bringing a Mechanistic Lens to the Development of New Transfer Hydroarylation Isodesmic Reactions for the Synthesis of Amides, Thioamides, Amidines, Alkenes and Ketones from Carboxylic Acids via Extrusion and Insertion Elementary Steps

“…CID of the adduct [CH 3 CuS 2 CCH 3 ] − gives CH 3 CS 2 − . Subsequently we showed that the copper complex [(Bphen)Cu(O 2 CC 6 H 5 )] 2− (Bphen=bathophenanthroline) also undergoes decarboxylation and the resultant organometallic complex, [(Bphen)Cu(C 6 H 5 )] 2− , reacts with CS 2 to form [(Bphen)Cu(S 2 CC 6 H 5 )] 2− [86] . These studies highlighted that sequential extrusion and insertion reactions could be used to transform coordinated ligands and spurred us onto the development of the new class of reactions coined as ExIn (Extrusion‐Insertion), which are discussed in detail below [87] …”