5-Diazo Meldrum's acid (DMA) undergoes a photo-induced Wolff rearrangement (WR). Recent gas-phase experiments have identified three photochemical products formed in a sub-ps scale after irradiation, a carbene formed after nitrogen loss, a ketene formed after WR and a second carbene formed after nitrogen and CO elimination (A. Steinbacher, et al. Phys. Chem. Chem. Phys., 2014, 16, 7290-7298). In...

A series of ten ferrocenyl, furyl, and thienyl mono- and biscarbene chromium(0) complexes were synthesized and characterized spectroscopically and electrochemically. The single crystal structure of the biscarbene complex [(CO)5Cr═C(OEt)-Fu'-(OEt)C═Cr(CO)5] (4a) was determined: C20H12Cr2O13; triclinic; P1; a = 6.2838(5), b = 12.6526(9), c = 29.1888(19) Å, α = 89.575(2), β = 88.030(2), γ = 87.423...

We report an efficient strategy for the asymmetric synthesis of trifluoromethyl-substituted cyclopropanes by means of myoglobin-catalyzed olefin cyclopropanation reactions in the presence of 2-diazo-1,1,1-trifluoroethane (CF3CHN2) as the carbene donor. These transformations were realized using a two-compartment setup in which ex situ generated gaseous CF3CHN2 is processed by engineered myoglobi...

A new mode of carbene-catalyzed heteroatom activation and asymmetric reactions is disclosed. The reaction starts with addition a carbene catalyst to (benz)imidazole-derived aldimine substrate. Subsequent oxidation proton transfer lead the formation catalyst-bound triaza-diene as key intermediate, in which nitrogen atom at site remote catalyst-substrate bond activated. This unusual intermediate ...

Operationally unsaturated (i.e., 16/18-electron) (PNPR)Re(H)4, where PNPR is N(SiMe2CH2PR2)2, is reactive at 22 degrees C with cyclic olefins. The first observed products are generally (PNPR)Re(H)2(cycloalkylidene), with hydrogenated olefin as the product of hydrogen abstraction from the tetrahydride. The tetrahydride complex with R = tBu generally fails to react (too bulky), that with R = cycl...

Recent work has shown that engineered variants of cytochrome P450BM3 (CYP102A1) efficiently catalyze non-natural reactions, including carbene and nitrene transfer reactions. Given the broad substrate range of natural P450 enzymes, we set out to explore if this diversity could be leveraged to generate a broad panel of new catalysts for olefin cyclopropanation (i.e., carbene transfer). Here, we t...

N-heterocyclic carbene-catalyzed reactions for the formation of aromatic compounds are reviewed. The subdivided into 4 types based on their activation modes. A brief summary achievements and challenges remaining in carbene (NHC)-catalyzed arene construction processes is provided at end this review. An outlook future research direction within field also given our own opinion knowledge trends dev...

We report an attempt to generate and characterize a triplet carbene, bis(2,4,6-trichlorophenyl)carbene ((3)1), in zeolites Y and L and in a molecular sieve VPI-5 in which a possible dimerization and reaction with the precursor of carbene are significantly retarded, thus making the triplet carbene longer lived than in solution at room temperature. The adsorption of a corresponding diazomethane (...