Methyl halide organocuprates

Quantum mechanical calculations have recently led to the suggestion that in the presence of Lewis acidic BF3 the reductive elimination reactions of trialkyl-copper(III) species may proceed via the formation of a Lewis acid-[P-cuprio(III) enolate] complex. DFT calculations have been employed to probe the mechanism for the SN2-substitution reaction of methyl halides and epoxides with lithium organocuprates(I) operate, with solvent effects, BF3 effects and trans-diaxial epoxide opening taken into account. Calculations have lately been combined with mass spectrometric results to probe equilibrium isotope effects for the coordination of C2H4 and C2D4 to otherwise bare coinage metal cations. ... 

Phenylthiomethyllithium (2a) was used for the homologation of primary halides in a two-step sequence first halogen displacement by reagent (2a) or the organocuprate derivative (in the case of allylic compound) and then replacement of the phenylthio group by iodo by heating the sulfide with a large excess of methyl iodide in 1 M sodium iodide solution in DMF (Scheme 16). 

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... 

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