Asymmetric Cu^I-Catalyzed Insertion Reaction of 1-Aryl-2,2,2-trifluoro-1-diazoethanes into Si–H Bonds

Abstract

An asymmetric copper(I)-catalyzed Si−H insertion reaction of 1-aryl-2,2,2-trifluoro-1-diazoethanes in dimethyl carbonate as green solvent alternative was developed. A C2-symmetric copper(I) diimine complex enabled the asymmetric insertion reaction to give enantioenriched (1-aryl-2,2,2-trifluoroethyl)silanes with excellent stereoselectivities (up to 98:2 er). Successful conversion of the silanes into the corresponding alcohols was performed with retention of stereochemistry. Mechanistic studies and DFT calculations support the proposed model for the observed stereoselectivities.

Recent Advances in Catalytic Alkyne Transformation via Copper Carbene Intermediates

“…In addition, the advancement made in modern era ligand design further accelerated the progress of copper carbene chemistry [ 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 ], especially in catalytic asymmetric versions. A variety of stereoselective reactions have been realized with copper carbene intermediates, including X–H insertion [ 59 , 60 , 61 , 62 , 63 , 64 ], cyclopropanation [ 65 , 66 ], cycloaddition [ 67 , 68 , 69 ], ylide formation [ 70 , 71 , 72 ], and others [ 73 , 74 ]. The representative advances in this area have been summarized by Doyle [ 75 , 76 , 77 ], Zhou [ 78 , 79 ], Wang [ 80 , 81 , 82 ], Pérez [ 83 , 84 ], and Davies [ 85 , 86 ].…”

Catalytic Asymmetric C(sp3)–H Carbene Insertion Approach to Access Enantioenriched 3-Fluoroalkyl 2,3-Dihydrobenzofurans

“…In this context, a strategy involving the insertion of fluoroalkyl carbenes into C­(sp 3 )–H bonds could potentially provide access to these molecules. Even though fluoroalkyl metal carbenes were widely explored in asymmetric cycloaddition, − X–H insertion, − and cross-coupling reactions, , the chemistry of such carbene insertion in asymmetric C–H bond functionalization remains an underdeveloped area, which is probably due to the intrinsic inertness of C­(sp 3 )–H bonds and the lack of an efficient fluoroalkyl carbene source (Figure b). − So far, there has been only one example, reported by the Arnold group, of the successful use of a fluoroalkyl carbene in an enantioselective C­(sp 3 )–H functionalization reaction using enzyme catalysis, which employed a potentially explosive, toxic, and pre-prepared trifluoromethyl diazomethane solution. Building on our continuous interest in the design and applications of fluoroalkyl N -sulfonylhydrazones, − we herein report a rhodium-catalyzed asymmetric carbene insertion into ether α-C–H bonds that uses easily decomposable fluoroalkyl N -triftosylhydrazones (triftosyl = 2-(trifluoromethyl)­benzenesulfonyl, Tfs) as operationally simple and bench-stable carbene precursors under mild conditions (Figure c).…”

Chiral Dirhodium Tetraphosphate-Catalyzed Enantioselective Si–H Bond Insertion of α-Aryldiazoacetates

“…Herein, we report a chiral spiro dirhodium tetraphosphate-catalyzed aryl-ester carbene insertion into the Si–H bond in excellent enantioselectivity. Surprisingly, the 2-substituted aryl diazoacetate substrates showed higher enantioselectivity in this insertion reaction, which is markedly different from the reaction using other chiral dirhodium catalysts . This research further demonstrated the privilege of chiral spirobiindan skeleton of catalysts in the chiral induction in asymmetric catalysis …”