Regiocontrolled synthesis of polysubstituted pyrroles starting from terminal alkynes, sulfonyl azides, and allenes.

1-Sulfonyl-1,2,3-triazoles, readily prepared from terminal alkynes and sulfonyl azides, react with allenes in the presence of a nickel(0) catalyst to produce the corresponding isopyrroles. The initially produced isopyrroles are further converted to a wide range of polysubstituted pyrroles through double bond transposition and Alder-ene reactions.

Synthesis of enaminones by rhodium-catalyzed denitrogenative rearrangement of 1-(N-sulfonyl-1,2,3-triazol-4-yl)alkanols.

Enaminones are synthesized by the rhodium(II)-catalyzed denitrogenative rearrangement reaction of 1-(N-sulfonyl-1,2,3-triazol-4-yl)alkanols, which are readily prepared from propargylic alcohols and N-sulfonyl azides. Intramolecular 1,2-hydride (or -alkyl) migration occurs with an intermediary α-imino rhodium(II) carbenoid species generated through denitrogenation of the 1,2,3-triazol-4-yl moiety. The resulting enaminones is converted into various heterocycles with replacement of the N-sulfonyl group.

Synthesis of α-amino ketones from terminal alkynes via rhodium-catalyzed denitrogenative hydration of N-sulfonyl-1,2,3-triazoles.

N-Sulfonyl-1,2,3-triazoles react with water in the presence of a rhodium catalyst to produce α-amino ketones in high yield. An intermediary α-imino rhodium(II) carbenoid undergoes insertion into the O-H bond of water. This transformation formally achieves 1,2-aminohydroxylation of terminal alkynes in a regioselective fashion when combined with the copper(I)-catalyzed 1,3-dipolar cycloaddition with N-sulfonyl azides.

Synthesis of cross-conjugated trienes by rhodium-catalyzed dimerization of monosubstituted allenes.

A rhodium(I)/dppe catalyst promoted dimerization of monosubstituted allenes in a stereoselective manner to give cross-conjugated trienes, which are different from those obtained by a palladium catalyst.

A discrete quadruple-decker phthalocyanine.

The reaction of a double-decker phthalocyanine (Pc) complex, bis(phthalocyaninato)lutetium ([LuPc(2)](-)), with cadmium acetate at 400 degrees C for 30 min under argon provided the first example of a discrete quadruple-decker Pc complex, 1. The structure of 1 was unambiguously determined through the use of high-resolution mass spectrometry, elemental analysis, and NMR techniques such as (1)H-(1)H COSY, (13)C-(1)H COSY, and NOE experiments. The absorption and magnetic circular dichroism spectra of 1 resembled those of [LuPc(2)](-) and [Lu(2)Pc(3)] rather than those of the neutral double-decker species [LuPc(2)](0), since the formal charge on each Pc moiety is 2-.