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A convergent and regioselective synthesis of silicon-bridged 4-arylpyridines has been developed through a rhodium-catalyzed [2+2+2] cycloaddition of silicon-containing diynes with nitriles. The absorption and emission properties of these compounds have been examined and could be tuned by varying the substituent on the benzene ring, as well as through the protonation or alkylation of the nitrogen atom on the pyridine ring. A catalytic asymmetric synthesis of silicon-centered axially chiral spirocyclic derivatives has also been achieved with high enantioselectivity by using a newly modified MeO-MOP (MeO-MOP=2-(diphenylphosphino)-2′-methoxy-1,1′-binaphthyl) derivative as the chiral ligand. These spirocyclic compounds were found to be CPL-active (CPL=circularly polarized luminescence), representing the first CPL-active compounds based on the chirality at silicon.

A convergent and regioselective synthesis of silicon-bridged 4-arylpyridines has been developed through a rhodium-catalyzed [2+2+2] cycloaddition of silicon-containing diynes with nitriles. The catalytic asymmetric synthesis of silicon-centered axially chiral spirocyclic compounds and their optical properties have also been investigated.

We have developed a metal-free, N-iodosuccinimide (NIS)-promoted, cascade strategy for the efficient synthesis of biologically important indeno[1,2-c]pyrroles via a [3+2] annulation process of enamine-alkynes. This methodology had shown a very broad scope for diversely functionalized enamines and alkynes. We have also developed a one-pot, multicomponent strategy for the direct synthesis of indeno-pyrroles from diynones via enamine-alkynes. Control experiments supported the involvement of NIS as an electrophilic activator via an ionic mechanism rather than a radical pathway.

The rhodium(I)-catalyzed intramolecular [2+2+2] cycloaddition between allenes, alkynes, and imines has been developed. This cyclization proceeds via a strained azarhodacycle, giving a 5,7-fused cyclic amide or a tricyclic product containing an 8-azabicyclo[3.2.1]octane skeleton in high yield.

The cyano-Schmittel cyclization of in situ-generated cyano-allenes has been carried out. The DFT calculation results suggest that the diradical pathway plays a major role in this cyclization. The reactions can be conveniently performed in a one-pot manner through cascade Sonogashira coupling of terminal cyano-ynes with organic halides, followed by base-promoted propargyl-allenyl isomerization/cyclization, leading to an efficient access to pyridine-fused polycyclic architectures. In particular, a large variety of aryl or heteroaryl rings such as furans, thiophenes and pyridines can be incorporated into the follow-up cyano-Diels–Alder reactions, highlighting the great synthetic utility of this chemistry.

I cyano what you did last summer: The cyano-Schmittel cyclization of in situ-generated cyano-allenes is described. The reactions can be conveniently performed in a one-pot manner through cascade Sonogashira coupling of terminal cyano-ynes with organic halides, followed by base-promoted propargyl-allenyl isomerization/cyclization, leading to an efficient access to pyridine-fused polycyclic architectures.

A new pathway to the synthesis of N-arylindoles has been developed that proceeds through an iron-catalyzed [2+2+2] cycloaddition reaction between diynes and indole-N-alkynes. The reaction is carried out in ethanol and employs a catalyst system that consists of iron(II) chloride tetrahydrate as the metal source, 2-[(2,6-diisopropylphenyl)iminomethyl]pyridine (dipimp) as the ligand, and zinc as the reducing agent. The method provides efficient access to 3-carbonyl/ester-substituted (indol-1-yl)arenes in good to excellent yields under green reaction conditions, and these products are structurally similar to other N-arylindole derivatives with potential medicinal value.

A new method for the synthesis of N-arylindoles by using a [2+2+2] cycloaddition reaction between diynes and indole-N-alkynes has been established. This protocol employs FeCl₂·4H₂O/2-[(2,6-diisopropylphenyl)iminomethyl]pyridine (dipimp)/Zn as the catalyst system and ethanol as the solvent and provides easy access to indole-N-substituted fused arenes under green reaction conditions.