Carbene Transfer and Carbene Insertion Reactions Catalyzed by a Mixed‐Ligand Copper(I) Complex

Abstract

The catalytic activity of the mixed‐ligand copper(I) complex [Cu(PPh3)2(κ2‐O,O"‐lact)] (1) {lact = l‐(+)‐lactate} has been investigated in carbene transfer and carbene insertion reactions. Complex 1 catalytically promoted the diastereoselective cyclopropanation of olefins in the presence of ethyl diazoacetate (EDA), under mild conditions, and with a low catalyst loading (1 mol‐%). In the case of internal alkenes, a trans/cis ratio of up to 93:7 was reached. Moreover, compound 1 easily promoted the insertion of the carbene fragment deriving from the decomposition of ethyl diazoacetate into O–H (alcohols and phenols) and N–H (amine) bonds, with formation of the corresponding ethyl 2‐alkoxyacetate, ethyl 2‐phenoxyacetate, and ethyl 2‐aminoacetate derivatives in good to high yields.

Mixed‐Ligand Mandelato‐Phosphine Copper(I) Complexes as Active Catalysts in Carbene Transfer Reactions

“…Finally, one diene was also employed as substrate, 2,5‐dimethyl‐2,4‐hexadiene (DMHD), showing a conversion into the corresponding chrysantemate ethyl esters in high yields (up to 90 %, entry 18). Overall, the yields in cyclopropane products are comparable to those reported for the analogous copper(I)‐lactate species [Cu(PPh 3 ) 2 (κ 2 ‐O,O“‐lact)] ( CuP2L ) [34] . Diastereoselectivities were comparable to previous publications as well: a 25 : 75 to 30 : 70 cis / trans ratio was recorded in the catalytic cyclopropanation of internal olefins, with the exception of α‐methylstyrene which was converted with a lower trans diastereoselectivity (ca.…”

“…Indeed, addition of ethyl diazoacetate to a solution of the olefin and the catalyst (1 % mol) led under mild conditions to the conversion of the substrate into the corresponding cyclopropane derivatives with high yields (Table 2). Like previous studies, [34] the catalytic runs were performed in dichloromethane, at room temperature. As known, side products deriving from EDA self‐coupling (i. e., diethyl maleate and diethyl fumarate) can also be generated.…”

“…In particular, compound CuP2L demonstrated high activity in catalytic carbene transfer reactions in the presence of diazoacetates. [34] To further explore the chemistry of copper compounds bearing α-hydroxycarboxylates, we now report the synthesis, the characterization, and the catalytic properties of new copper(I) coordination compounds bearing a mandelate ligand.…”

“…In fact, we reported on mixed ligand copper(I) complexes containing a lactate ion, [Cu(PPh 3 ) 2 (κ 2 ‐O,O “ ‐lact)] [32] ( CuP2L ) and [Cu 2 (μ‐dppm) 2 (κ‐O‐lact)(μ‐κ‐O‐lact)] ( CudppmL ) [33] (lact= l ‐(+)‐lactate). In particular, compound CuP2L demonstrated high activity in catalytic carbene transfer reactions in the presence of diazoacetates [34] . To further explore the chemistry of copper compounds bearing α‐hydroxycarboxylates, we now report the synthesis, the characterization, and the catalytic properties of new copper(I) coordination compounds bearing a mandelate ligand.…”

Defect Engineering of Copper Paddlewheel-Based Metal–Organic Frameworks of Type NOTT-100: Implementing Truncated Linkers and Its Effect on Catalytic Properties

“…Transition metal-catalyzed carbene transfer from diazo derivatives to olefins is a powerful method to give cyclopropane rings. − Iglesias and co-workers prepared two imine-linked polymer–organic frameworks (POFs) and modified them with Cu by postsynthetic metalation . They compared the catalytic activity of both Cu 1+ - and Cu 2+ -based POFs for the cyclopropanation of alkenes and found that the Cu 1+ -modified material had higher activity.…”