An efficient procedure for the preparation of Z-enamides has been developed, involving the reaction of primary amides with conjugated olefins using a Pd/Cu cocatalyst system. It was found that certain additives, such as phosphine oxides and phosphonates, increase the efficiency of the reaction in nonpolar solvents under an oxygen atmosphere, thus producing a variety of Z-enamides in high yields with excellent stereoselectivity under Wacker-type conditions. The oxidative amidation reaction has a broad substrate scope, allowing alkyl, aryl, and vinyl amides to react with olefins conjugated with ester, amide, phosphonate, and ketone groups. The notable preference for the formation of Z-enamides is presumably due to the presence of an intramolecular hydrogen bond between the amido proton and the carbonyl oxygen. The energy difference between two plausible sigma-alkylamidopalladium intermediates, leading to Z- and E-isomeric enamide products, respectively, was calculated to be 4.18 kcal/mol. The beta-hydride elimination step is assumed to be a stereochemistry-determining step in the overall oxidative amidation process, with the energy level for the transition state leading to the Z-enamide being 5.35 kcal/mol lower than that leading to the E-isomer. The efficiency of photoisomerization between Z- and E-enamides was observed to be largely dependent on the substrates' substituents, and certain E-enamides could be obtained in synthetically useful yields by photoirradiation of Z-isomers. Synthetic application of the present method was successfully demonstrated by a direct formal synthesis of cis-CJ-15,801.

A new synthetic methodology for the generation of cyclic amidines has been developed by the reaction of 1,n-aminoalkynes with electron-deficient azides using a ruthenium catalyst at ambient temperature. The reaction proceeds most likely via a tandem sequence of intramolecular hydroamination of aminoalkynes, cycloaddition of azides with the resulting enamines, and rearrangement of triazoline intermediates. It demonstrates, as the proof-of-principle, that an equilibria cascade sequence can be favorably driven by an irreversible step, thus enabling a facile one-pot synthetic route to deliver molecular complexity under unprecedented mild conditions without relying on the traditional linear approaches.

Phosphoryl azide was successfully employed as an efficient reacting partner in the Cu-catalyzed three-component reaction with 1-alkynes and amines to produce the corresponding phosphoryl amidines in high yields. A range of fruitful applicability of the produced amidines was also demonstrated such as an alkoxide exchange and asymmetric alpha-alkylation of optically active BINOL-derived amidines.

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Cycloamidines are prepared by combining an intramolecular hydroamination with a 1,3-dipolar cycloaddition of azides to the enamine double bond formed in the first step. In the case of enamines with an exo-methylene moiety, spiro triazolines are formed which rearrange to cycloamidines of type (IV) upon release of diazomethane. Enamines with an endo double bond furnish fused triazolines which release dinitrogen upon migration of a methyl group yielding cycloamidines of type (III). -(CHANG*, S.; LEE, M.; JUNG, D. Y.; YOO, E. J.; CHO, S. H.; HAN, S. K.; J.