Additions with Organocopper Reagents Derived from CuCN-2LiBr-Based Active Copper

Conjugate Additions with Organocopper Reagents Derived from CuCN 2LiBr-Based Active Copper 

The halide (0.25-0.30 equiv based on 1 equiv of CuCN) was transferred to the active copper solution at -35°C. After 15 min, the flask was cooled to -78°C. A two- to threefold excess of TMSCl, in respect to the equiv of 1,4-adduct, was injected neat into the flask (a sixfold excess of TMSCl was used for entry 6, Table 5.9). The 1,4-adduct was dissolved in THF (10 ml) in a separate vial and delivered dropwise to the stirring organocopper solution. After 1.5 h at -78°C, the flask was gradually warmed to room temperature. The enone, 2-cyclohexen-l-one, was injected neat at -90°C, warmed to -78°C, and stirred for Ih. 3-(3-Methyl-2-butenyl)cyclohexanone was the sole product isolated upon workup by standard methods. 

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