Hydroamination carbocyclization

Trivinyl benzene may be utilized in a hydroamination/carbocyclization process that is initiated by an intramolecular anft -Markovnikov addition of n-propylamine followed by an intramolecular hydroamination and a highly diastereoselective car-bocyclization step (44) [100]. 

Hydroamination/bicyclization of aminodialkenes, aminodialkynes, and amino-alkenynes opens a straightforward route to pyrrolizidines and indolizidines in a tandem C-N and C-C bond forming process. An important prerequisite for the success of this reaction sequence is a sufficient lifetime of the rare-earth metal alkyl intermediate formed in the initial insertion process of the alkene/alkyne in the Ln-amide bond in order to permit the carbocyclization step (Scheme 9) [99,174],... 

A sequence of inter- and intramolecular hydroaminations and carbocyclizations of the aminoalkeneyne 34 substrate allows the facile assembly of the tricyclic polyheterocycle 35 with exclusive trani -diastereoselectivity (43) [99]. 

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