Allylic amine isomerization double-bond migration

Allylic amide isomerization, 117 Allylic amine isomerization ab initio calculations, 110 catalytic cycle, 104 cobalt-catalyzed, 98 double-bond migration, 104 isotope-labeling experiments, 103 kinetics, 103 mechanism, 103 model system, 110 NMR study, 104 rhodium-catalyzed, 9, 98 Allylnickel halides, 170 Allylpalladium intermediates, 193 Allylsilane protodesilylation, 305 Aluminum, chiral catalysts, 216, 234, 310 Amide dimers, NMR spectra, 282, 284 Amines ... 

Migration of the double bond of the cyclic olefin formed by the RCM has also been observed [35]. RCM of the diene 77 by 69 in refluxing dichloromethane resulted in the formation of considerable amounts of the unexpected cyclic olefin 79 in addition to 78 (Eq. 12.31) [35a[. It was also noted that the formation of 79 was effectively suppressed by the addition of amine to the dichloromethane solution or employment of diethylether as solvent, which implies participation of proton in the isomerization reaction. It was also noted that a terminal vinyl group with a free tertiary allylic hydroxyl group accelerates RCM, rather than its methyl ether derivative. These results suggested some interaction between the alkylidene complex 69 with hydroxyl proton in situ. 

In the latter case the S N allyl group migration is only efficient when Pd catalysis is employed, otherwise, at much higher temperatures, a double bond isomerization occurs first and is then followed by an S C allyl shift by means of a thio-Claisen rearrangement. As the appropriate 5-allyl thioimidates are easily prepared by alkylation of thioamides with allyl halides, the overall process is an 5n substitution of an allylic halide by an amine, a reaction which is difficult to achieve directly. 

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