Nitrogen nucleophiles inter-intramolecular reactions

Early on, Heck and co-workers found that intra- and intermolecular coupling reactions of haloalkenes with alkenes in the presence of secondary amines gave allylamines.t t Apparently, an intermediate 7r-allylpalladium complex is formed by rearranganent of the (7-homoallylpalladium intermediate (see above, B.ii) and in turn attacked by the nitrogen nucleophile. Excellent yields of tertiary aUylamines are obtained in this three-component coupling (Scheme As far as the outcome is concerned, analogous inter-intra- as well as fully intramolecular processes have been estabhshed (Scheme 30 see Table... 

The second set of examples involves the use of thionium ions as electrophiles in inter- and intramolecular processes to obtain a-substituted sulfides (see 24 25, Scheme 20.7T which is the most common type of Pummerer reaction. Applications of this classical Pummerer rearrangement are exemplified in the synthesis of trans-solamin, the synthesis of indolizidine alkaloids, and the synthesis of the CDE ring of erinacine E. The first exanple fScheme 20.10 uses Pummerer chemistry in the generation of a thionium ion, which reacts in an intermolecular tin-mediated ene reaction the second one fScheme 20.11 uses Pummerer chemistry to introduce a nitrogen-containing heterocycle by intramolecular addition to form the coniceine core and the third example fScheme 20.12 is an intramolecular silicon-induced Pummerer reaction with oxygenated nucleophiles applied to the synthesis of a precursor of erinacine. Details of these Pummerer-based strategies are discussed below. 

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