Aminodienes, conjugated

Both [2 + 2] and [4 + 2] cycloadditions have been observed in the reaction of dienamines with sulfenes. For example, reaction of cross-conjugated dienamine 202 with sulfene afforded a mixture of 203 and 204 (equation 44)111. Also, enamines of 1-tetralone (205, 206) can react as enamines or as aminodienes with phenylsulphene giving 207-209 (equation 45)112. 

Rare-earth metal complexes have proven to be very efficient catalysts for intramolecular hydroamination reactions involving aminoalkenes, aminoalkynes, aminoallenes, and conjugated aminodienes [88, 97]. They are significantly less efficient in intermolecular hydroamination reactions and only a limited number of examples are known [98-102]. The difficulties in intermolecular hydroamination reactions originate primarily from inefficient competition between strongly binding amines and weakly binding alkenes for vacant coordination sites at the catalytically active metal center. 

Hong S, Kawaoka AM, Marks TJ. Intramolecular hydroami-nation/cyclization of conjugated aminodienes catalyzed by organolanthanide complexes.Scope, diastereo and enantiose-lectivity, and reaction mechanism. J. Am. Chem. Soc. 2003 125(51) 15878-15892. 

The intramolecular hydroamination reaction of aminoalkenes and other substrates involves two key steps in the catalytic cycle. Although the insertion step is generally perceived as the rate-determining step of the process, this may not be true for aU substrate classes. The hydroamination/cyclization of aminoalkenes differs significantly from reactions involving aminoalkynes, aminoaUenes, and conjugated aminodienes from a thermodynamic point of view. The alkene insertion step of the... 

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