Amine-Claisen rearrangement

Fischer DF, Xin ZQ, Peters R (2007) Asymmetric formation of allylic amines with N-substimted quaternary stereocenters by Pd -catalyzed Aza-Claisen rearrangements. Angew Chem Int Ed 46 7704-7707... 

Xin ZQ, Fischer DF, Peters R (2008) Catalytic asymmetric formation of secondary allylic amines by Aza-Claisen rearrangement of trifluoroacetimidates. Synlett 1495-1499... 

A related amination/rearrangement/cyclization tandem sequence had been introduced by Cossy [49]. Starting from cyclic epoxyketones 224 the reaction with propargylamines 225 caused an oxirane-opening condensation process to generate the enaminoketones 226. Upon heating in toluene to reflux, aza-Claisen rearrangement delivered the intermediate allenyl imines 227, which... 

An uncatalyzed amination/aza-Claisen rearrangement/cyclization cascade described by Majumdar et al. was terminated by a final six-membered ring for-... 

The asymmetric aza-Claisen rearrangement of allyl imidates, (86) (87), has been shown to be catalysed by homochiral cationic palladium(II) complexes, and a series of enantiopure cyclopalladated ferrocenyl amines and imines have been... 

The behavior of tra s-[RuCl(=C=C=C=CH2)(dppm)2][PF6] towards the tertiary amine allyldimethylamine merits to be highlighted since the reaction led to the dimethylamino-allenylidene complex 32 through an Aza-Cope (or Claisen) rearrangement of the initially generated quaternary vinyl-allyl-ammonium salt [RuCl C=CC(NMe2CH2CH=CH2)=CH2 (dppm)2][PF6] (31) (Scheme 8) [47]. 

The 3-aza-Claisen rearrangement concerning the rearrangement of aUyl vinyl amines, contrary to its Cope analogue, has not been used extensively to form carbon-carbon bonds, probably due to the high temperatures (>180°C) required for the uncatalysed variant and to the limited number of catalysts available for promoting the reaction at moderate temperatures (equation 4). 

Secondary aliphatic amines were found to give higher yields of thienothiophenes than did tertiary amines, which are weaker bases. A maximum ratio of thienothiophenes to thienothiopyrans of about 4 1 was achieved at 145° with diisopropylamine as cat yst and DMSO as solvent. Only thienothiopyrans were formed in DMF in the presence of the same catalyst The amines promote nucleophilic cyclization of Claisen rearrangement products into thienothiophenes. Since thienothiophenes are resistant to treatment with potassium t-butoxide in DMSO and thienothiopyrans form resinous products under these conditions, the method is a convenient route to pure thienothiophenes 35 and 42 in yields of up to 40%. ... 

Allyl amines, allyl thioethers, and allylferrocenylselenide react analogously with butatrienylidene complex 10 by initial addition to C3 and subsequent hetero-Cope or hetero-Claisen rearrangement (Scheme 3.23) [21, 42-45]. 

The thermolysis of 2-(propargylthio)thiophene (350) and the 3-isomer (351) in the presence of diisopropylamine in a polar solvent such as DMSO led to the formation of the thienothiophenes (56) and (356) in yields of 53% and 65%, respectively. The by-products of these reactions were the thienothiopyrans (354) and (355), which could be conveniently eliminated by treatment with potassium f-butoxide prior to workup. A thio-Claisen rearrangement of (350) and (351) could lead to the presumed allenic thione intermediates (352) and (353), which then rearrange to the observed products (Schemes 121 and 122). In the absence of the amine catalyst, only thienothiopyrans were formed. The ratio of thieno-thiophene to thienothiopyran in the reaction mixture was dependent on the nature of the amine and the solvent used. Diisopropylamine favored the formation of thienothiophenes in... 

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