The existence of an ?3 organocopper(III) intermediate in the reaction of the Gilman reagent Me2CuLi�LiI with a,�-unsaturated carbonyl compounds was proposed long ago, but only recently confirmed experimentally. Upon warming, the ?3 intermediate can yield 1,2- or 1,4-addition products or a mixture of both. In further experiments the ?3 species has been reacted with one additional equivalent of methyllithium at low temperatures to form two ?1 organocuprate(III) species (Scheme 1). Upon warming, they undergo reductive elimination to the usual addition products. The details of these experiments will be presented along with further NMR studies on the structural aspects of the organocopper intermediates and the dependence of product distribution on the R group, the alkyllithium reagent or additional Lewis base.

Investigation of η<sup>1</sup> and η<sup>3</sup> intermediates in the conjugate addition of organocuprates to enones and enals

244th National Meeting (2012)

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Investigation of η1 and η3 intermediates in the conjugate addition of organocuprates to enones and enals

Investigation of η¹ and η³ intermediates in the conjugate addition of organocuprates to enones and enals