Hetero-multicomponent Coupling Reactions

Because of the weak C-Te bond, organotellurides can serve as efficient carbon radical precursors [13]. However, they are generally unstable to handle, unlike the 

Multicomponent Coupling Reactions Mediated by Croup 14 Radicals 

Allyltin compounds are unique players in radical chemistry, since they are able to serve both as radical acceptors and at the same time as radical chain mediators to provide tin radicals [27]. Because of the nucleophilic nature of ordinary alkyl radicals, the addition of an alkyl radical to tributylallyltin is not very fast, yet fast enough to transfer the radical chain [28], This is an advantage for the controlled 

The combination of tin enolate-mediated radical reactions with carbonylation is highly successful. Three-component coupling reactions involving an alkyl 

---

D. A. Powell, R. A. Batey, Org. Lett. 2002, 4, 2913-2916. Total synthesis of the alkaloids martinelline and martineUic acid via a hetero Diels-Alder multicomponent coupling reaction. 

Another recent development in the field of palladium-catalyzed reactions with alkynes is a novel multicomponent approach devised by the Lee group. Starting from a-bromovinyl arenes and propargyl bromides, the assembly ofeight-membered car-bocycles can be realized via a cross-coupling/[4+4] cycloaddition reaction. The authors also presented the combination of a cross-coupling and homo [4+2], hetero [4+2], hetero [4+4] or [4+4+1] annulation leading to various cyclic products [147]. 

---