Carboxamidate pyrrolidinones

In a correction to previous work, the cyclization of 4-ureidobutyric acids with thionyl chloride has been shown (by NMR spectroscopy) to result in pyrrolidinone carboxamide derivatives and not aryl perhydro-l,3-diazepine-2,4-diones <00JHC111>. Optimization of the geometry of l-(o-nitrophenyl)-2-phenyl-l//-4,5,6,7-tetrahydro-l,3-diazepine has been undertaken using computer-based molecular modelling, and correlations made with theoretical and experimental UV spectra . 

Doyle s rhodium(n) carboxamidate complexes are undisputedly the best catalysts for enantioselective cyclizations of acceptor-substituted carbenoids derived from diazo esters and diazoacetamides, displaying outstanding regio- and stereocontrol.4 These carboxamidate catalysts consist of four classes of complexes pyrrolidinones... 

A one-step synthesis of 4,5-disubstituted iniidazole-2-carboxamides reacts a 1,2-diketone monophenylhydrazone with aminomalonamide (Scheme 4.1.5). Yields lie in the range 42-77%. Reactions are carried out in I-methyl-2-pyrrolidinone at 100°C, and the method can be adapted to the preparation of 2-cyanoimida7.oles by subsequent dehydration of the amides with phosphoryl chloride [42]. 

The mechanism by which selectivity is induced in rhodium mediated asymmetric cyclopropanations is not clear. What is known is that the pyrrolidinone of the MEPY catalyst is bonded to the rhodiums through the carboxamide, with the nitrogens cis to each other, as shown in Figure 6.11 [113]. This arrangement places the two carbomethoxy groups cis to each other on both sides of the catalyst. With... 

ChiralcarboxamMatecomplexes. After exchanging the ligands of dirhodium tetraacetate to chiral pyrrolidinones (as well as their heteroatom analogs) bearing a methyl ester at C-5 new carboxamidate complexes are formed. These are catalysts of choice for enantioselective intramolecular metal carbene transformations. One such complex is particularly effective for the formation of P-benzyl-y-butyrolactones from hydrocinnamyl diazoacetates. The lactones are useful for the synthesis of some lignans. 

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