Iron-catalyzed reactions allylic substitution

The reductive coupling of of dienes containing amine groups in the backbones allows for the production of alkaloid skeletons in relatively few steps [36,46,47]. Epilupinine 80 was formed in 51% yield after oxidation by treatment of the tertiary amine 81 with PhMeSiH2 in the presence of catalytic 70 [46]. Notably, none of the Irons isomer was observed in the product mixtine (Eq. 11). The Cp 2LuMeTHF was found to catalyze cyclization of unsubstituted allyl amine 82 to provide 83. This reaction proceeded in shorter time and with increased yield relative to the same reaction with 70 (Eq. 12) [47]. Substitution of either alkene prevented cycUzation, possibly due to competitive intramolecular stabilization of the metal by nitrogen preventing coordination of the substituted olefin, and resulted in hydrosilylation of the less substituted olefin. 

A broad variety of acids can be applied ranging from aromatic and heteroaromatic acids, simple aliphatic acids to a,p-unsaturated acids. The configuration of stereogenic centers in a-position is fully retained. Acyliron complexes are proposed as intermediates. A (trichloro)[bis(imidazolonyl)pyridine]iron complex catalyzes the alkylative cyclization of 2-chloro-1,6-dienes and the deallylation of allyl malonates in the presence of triethylaluminum (Scheme 4-356). The yields, however, vary and depend very much on the substrate. 2-Substituted 2-allylmalonates can be demetalated under the same reaction conditions. 

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