Metal salt catalyzed carbenoid—XIII

Synthesis, structures, and catalytic reactivity of bis(N-heterocyclic carbene) supported diphenyldiazomethane and 1-azidoadamantane complexes of nickel

“…Most transition-metal mediated cyclopropanation reactions are proposed to proceed through a metallacarbene intermediate, [77][78][79][80] but this is not always the case. Peace has proposed diazoalkane attack on a Cu-coordinated olefin as one of the pathways by which cyclopropanes are formed with [(MeO) 3 P] 2 CuI or Cu(acac) 2 , [81] and Maulide has proposed olefin activation for a series of Au-catalyzed intramolecular cyclopropanations where the putative metallacarbene complex is inactive for cyclopropanation. [82] A metallocarbene intermediate is unlikely with 3-IMes because, at the elevated temperature required for cyclopropanation, the diazoalkane ligand dissociates from the metal center rather than form a carbene (vide supra).…”

“…Thus, we propose a catalytic cycle where 1-IMes (I) activates the olefin (II) for electrophilic attack by the diazoalkane (Scheme 8) in a similar manner to that observed by Peace. [81] N 2 elimination from the intermediate complex (III) would likely proceed with little to no barrier, and dissociation of the cyclopropane or displacement by olefin should be facile to turn over the catalytic cycle.…”

Catalytic Oxy‐Functionalization of Methane and Other Hydrocarbons: Fundamental Advancements and New Strategies

“…An interesting extension of organic carbenes is the utilization of transition metal carbene complexes for CÀH bond activation (Scheme 1). The first examples of catalytic intermolecular functionalization by carbene insertion using diazo compounds as the carbene source were based on copper (CuSO 4 [26] and Cu(acac) 2 [27] ). In both cases the yields were low but the results opened a new area of research.…”

The carbene insertion methodology for the catalytic functionalization of unreactive hydrocarbons: No classical C–H activation, but efficient C–H functionalization

“…And this is in spite of the time passed from the first example of this reaction, described by Scott and DeCicco more than 30 years ago, 16 of the use of copper sulfate [eqn (5)] to promote the decomposition of ethyl diazoacetate (5) (N 2 CHCO 2 Et, EDA) and the subsequent formal insertion of the CHCO 2 Et unit into the C-H bond of cyclohexane in low yield. Shortly after this report, Wulfman et al 17 Since then, we have found that not only copper, 22,23 but also silver 24 and gold, 25,26 in combination with either trispyrazolylborate (Tp x , homoscorpionate) 27 or N-heterocyclic carbene (NHC) ligands can be employed as the catalysts for the functionalization of alkanes.…”