Tandem intramolecular carbolithiation–transmetallation: from lithium to copper or boron chemistry

Lithium/copper transmetallation from the organolithium intermediate (obtained via intramolecular carbolithiation of the acyclic organolithium , generated by a chlorine–lithium exchange) gives the corresponding organocopper intermediate . This intermediate reacts with eletrophiles, such as allylic or propargylic halides, acyl chlorides or α,β-unsaturated carbonyl compounds giving the expected compounds , which are not possible to be obtained directly from the organolithium . On the other hand, lithium/boron transmetallation affords the corresponding alkylboronic acid which, after palladium-catalysed Suzuki–Miyaura cross-coupling reaction with different aryl bromides gives the expected products with modest yields, the corresponding Ullman biarylic homocoupling products being the major by-products.