New reactivity of functionalised organolithium compounds in the presence of Cu(I) or Cu(II) salts: conjugate addition, acylation or dimerisation

The reaction of functionalised organolithium compounds 1 with electrophilic olefins 2 in the presence of copper(I) iodide and HMPA in THF at −78°C leads, after hydrolysis with a saturated solution of ammonium chloride, to the corresponding products 3 resulting from a conjugate addition. The same process but using an acyl chloride instead of the electrophilic olefins affords the expected ketone 4 from an acylation process. Finally, when intermediates 1 are treated with copper(II) chloride in THF at −78°C, the corresponding dimers 5 are isolated after the same hydrolytic treatment.