Enamines iron catalyzed

Systematic studies on the isomerization of W-allylamides 24 and -imides to aliphatic enamides 25 were carried out with iron, rhodium, and ruthenium complexes as catalysts, Eq. (8). Regrettably, no prochiral substrate was applied for the rhodium catalyst bearing polymer-anchored DIOP [33]. In the framework of a study on the conjugative interaction in the isomerization of 1-azabicyc-lo[3.2.2]non-2-ene 26 to orthogonal enamine 27, catalyzed by either f-BuOK or RuH(NO)(PPh3)3, the enamine formation was calculated to be favored by 4 kcal mob, Eq. (9) [34]. Recently, the palladium-catalyzed isomerization of the N-acyl-2,5-dihydropyrroles 28 to N-formyl-2,3-dihydropyrroles 29 was reported, Eq. (10) [35]. 

In an early report, Carbonaro et al. and, later. Genet and Ficini described an iron-catalyzed Diels-Alder reaction of ynamines with 1,3-butadiene which led to the enamine 4 in 80% yield without aromatization at 25 °C (Scheme 13.2) [1],... 

In a similar manner diethyl maleate (actually diethyl fumarate since the basic enamine catalyzes the maleate s isomerization upon contact) forms unstable 1,2 cycloadducts with enamines with hydrogens at temperatures below 30°C (37). At higher temperatures simple alkylated products are formed (41). Enamines with no )3 hydrogens form very stable 1,2 cycloadducts with diethyl maleate (36,37,41). The two adjacent carboethoxy groups of the cyclobutane adduct have been shown to be Irons to one another (36,37). 

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