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Homogeneous perdehydrogenation of saturated bicyclic 2,6-dimethyldecahydro-1,5-naphthyridine and perhydrogenation of aromatic 2,6-dimethyl-1,5-naphthyridine with release and uptake of five molecules of H2 are efficiently achieved by iridium complexes bearing a functional bipyridonate ligand. Successive perhydrogenation and perdehydrogenation of 2,6-dimethyl-1,5-naphthryridine using a single iridium complex also proceed with the reversible interconversion of the catalytic species, depending on the presence or absence of H2.

Alkenyl(cyanato)benzenes undergo the title reaction to give benzofuran- and benzopyran derivatives in a highly chemo- and regioselective manner.

Alkyl carbon-oxygen bonds of alkyl aryl ethers bearing suitable coordination sites were efficiently cleaved by treatment with nickel(II) chloride and zinc in p-xylene under neutral conditions.

Treatment of o-alkoxybenzaldoxime ethers 3 with an equimolar amount of NiCl2 and 3 equimolar amounts of Zn gave o-alkoxybenzonitriles 4 in good yields. It is suggested that the reaction proceed via coordination of the ether oxygen atom of alkyl ether moiety to low-valent metal species.

One pot synthesis of optically active 4-isoxazolines was achieved by asymmetric addition of alkynylzinc reagents to nitrones utilizing di(t-butyl) (R,R)-tartrate as a chiral auxiliary followed by cyclization. By addition of dimethylzinc, the cyclization step was accelerated to afford the corresponding 4-isoxazolines with up to 93% ee. Furthermore, a cyclized zinc intermediate could be trapped with formaldehyde to give the corresponding 2,3,4,5-tetrasubstituted 4-isoxazoline with 85% ee.

The catalytic asymmetric addition of alkynylzinc reagents, which were prepared in situ from dimethylzinc and 1-alkynes, to nitrones was achieved by utilizing di(t-butyl) (R,R)-tartrate as a chiral ...

The asymmetric addition of alkynylzinc reagents, prepared in situ from dialkylzinc and 1-alkynes, to nitrones was achieved by utilizing di(t-butyl) (R,R)-tartrate as a chiral auxiliary to afford the corresponding optically active (R)-α-substituted propargylic N-hydroxylamines. By the addition of product-like N-hydroxylamine, unprecedented enhancement of enantioselectivity was observed to afford the N-hydroxylamines up to 95% ee.