Copper organocuprate reagents

The reaction of tert-alkyl Grignard reagents with carboxylic acid chlorides in the presence of a copper catalyst provides ieri-alkyl ketones in substantially lower yields than those reported here.4,14 The simplicity and mildness of experimental conditions and isolation procedure, the diversity of substrate structural type, and the functional group selectivity of these mixed organocuprate reagents render them very useful for conversion of carboxylic acid chlorides to the corresponding secondary and tertiary alkyl ketones.15... 

Table 5 Formation and Acylation of Stoichiometric Organocuprate Reagents prepared from Rieke Copper...

In the example in Scheme 1.170, the TJ-alkene is formed from the -alkenyl halide. Likewise, the Z-alkene is formed selectively from the Z-alkenyl halide. Alkenyl tri-llates are also good substrates for alkylation with organocuprate reagents. Treatment of the alkenyl triflate 170 with methyl magnesium bromide and copper(I) iodide as catalyst, gave the alkylated product 171, used in a synthesis of paeonilactone A (1.171). 27... 

Addition of organocuprate reagents to a,j8-enones is solvent dependent indeed the addition is retarded by the inclusion of HMPA in the reaction medium to the extent that halide-ion displacement occurs preferentially. " Copper-catalysed conjugate addition of the magnesio-acetal (25) to cyclic enones is the key step in a new cyclopentene annelation procedure [equation (36)]. ... 

Similarly to the alkyl derivatives, the most common route for arylcopper compounds is the reaction of a copper halide and aryllithium compounds (Equation (4)). Organocuprates with aryl groups are obtained by using an appropriate excess of the lithium reagent. Magnesium aryls have also been employed in transmetallation reactions with Cu(l) salts to yield both arylcopper compounds and arylcuprates (Equations (5) and (6)). 

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