Carbamates nitrogen-allylic substitution reactions

In contrast, reactions catalyzed by la were typically conducted with added [Ir (C0D)C1]2 to trap the K -phosphoramidite ligand after dissociation, and thereby, to leave the unsaturated active catalyst. Under these conductions, as much as half of the iridium in the system is present in an inactive acyclic species. In contrast, when ethylene adduct lb is used as the catalyst, all of the iridium belongs to the active metalacyclic species. Hartwig and coworkers have recently taken advantage of the increased availability of the active catalyst generated from lb to develop new allylic substitution reactions. These new processes include the reactions of carbamates, nitrogen heterocycles, and ammonia. 

A wide application of Newcomb s method provides a variety of N-heterocyc-lic systems, such as perhydroindoles, pyrrolizidines and aza-brigded bicycles [59, W, 146], The mild reaction conditions are compatible with several funtional groups of the substrate and several trapping agents to functionalize the cyclized product. 2-Substituted pyrrolizidines 132 are accessible by tandem cyclization of iV-allyl-substituted PTOC carbamate 131. In this case the allyl group on the nitrogen serves as an internal trap for the intermediate carbon radical. The Af-methylcyclohept-4-enaminium radical cation, produced from the corres-... 

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