Copper-Catalyzed Enantioselective Cyclopropanation of Internal Olefins with Diazomalonates

Abstract

The first enantioselective copper catalyzed cyclopropanation of internal olefins with diazomalonates is reported. This process provides a new method for the synthesis of chiral 1,1-cyclopropane diesters. With a chiral bi-side arm bisoxazoline-copper(I) complex, the reaction performed well over a series of substrates, giving the desired products in good yields (up to 95%) and excellent enantioselectivities (90-95% ee).

Phosphine-catalysed intermolecular cyclopropanation reaction between benzyl bromides and activated alkenes

“…Of many methods developed, 2 metal-mediated [1+2] cycloaddition of carbenoids or metallocarbenes with electron-rich/-neutral alkenes has been widely exploited. 3 Some metal-free approaches, including aminocatalysis, 4 phase transfer catalysis, 5 etc , 6 have also contributed significantly to this field.…”

A Green Chemistry Approach toward the Stereospecific Synthesis of Densely Functionalized Cyclopropanes via the Solid-State Photodenitrogenation of Crystalline 1-Pyrazolines

“…The synthesis of cyclopropyl-containing compounds remains of great importance to the organic chemistry community, as this structurally unique motif is prevalent in complex natural products, bioactive drug candidates, and extensive sp 3 -rich small-molecule libraries. − As a result, notable cyclopropanation methodologies, such as nucleophilic or carbenoid-mediated additions to double bonds, continue to be developed. − Recently, the Marek Group described the regio- and diastereoselective synthesis of penta- and hexa-substituted cyclopropanes through copper-catalyzed carbomagnesiation of persubstituted cyclopropenes. , These highly strained cyclopropenes are well-suited to undergo directed carbometalation reactions with a number of organometallic reagents. The resulting metalated cyclopropanes can be subsequently employed in a variety of useful synthetic transformations that are commonly associated with polysubstituted cyclopropanes.…”

Cyclopropanation of poly(isoprene) using NHC‐Cu(I) catalysts: Introducing carboxylates

“…[10] Frequently used metal-catalysts based on palladium and rhodium, [11][12][13][14] but also Cu(I/II)-based catalysts were considered for such cyclopropanations. [15][16][17][18] Cyclopropanation of poly(diene)s, like poly(isoprene) (PI) or poly(butandiene), are only rarely known examples in the literature. Thus for instance a cyclopropanation of predominantly 1,2-syn-polybutadiene (1,2 linkage $70 mol%) has been reported with methyl diazoacetate and a copper(I) triflate benzene complex ([Cu OTf]Á0.5C 6 H 6 ) as catalyst, achieving up to 33 mol% cyclopropane modification corresponding to the polymer double bonds in dichloromethane (DCM), [3] albeit no preference to 1,2-or 1,4-linkages could be observed.…”

“…[ 10 ] Frequently used metal‐catalysts based on palladium and rhodium, [ 11–14 ] but also Cu(I/II)‐based catalysts were considered for such cyclopropanations. [ 15–18 ]…”