An efficient synthesis of dibenzo[b,f]oxepines and benzo[b]oxepines via FeCl3-catalyzed alkyne-aldehyde metathesis reaction is described. Structurally diverse dibenzo[b,f]oxepines and benzo[b]oxepines have been achieved in good yields with high regio- and chemoselectivity under mild conditions. Notably, among the various catalysts such as Fe(III), Au(III), In(III), Zn(II), Ag(I) and triflic acid, the alkyne-aldehyde metathesis reaction of 2-(2'-phenylethynyl-phenyloxy)-benzaldehyde is only catalyzed by environmentally friendly and sustainable iron(III) chloride.

A simple and efficient synthesis of complex pyrrolo[1,2‐a]quinoline derivatives was achieved through sequential reactions that involved an iron(III)‐catalyzed synthesis of N‐(2‐alkynylaryl)pyrroles and a gold(III)‐catalyzed intramolecular hydroarylation reaction. This strategy tolerated a wide range of substrates with a variety of sensitive functional groups and afforded the corresponding pyrrolo[1,2‐a]quinoline derivatives in moderate to good yields. The ease of availability of the starting materials and the generality of the reaction sequences make it a highly attractive strategy to synthesize a diverse range of pyrrolo[1,2‐a]quinoline derivatives. Moreover, a preliminary photophysical study showed that the resulting molecules exhibit good fluorescence activity.

We examine the integral cohomology rings of certain families of 2n-dimensional orbifolds X that are equipped with a well-behaved action of the n-dimensional real torus. These orbifolds arise from two distinct but closely related combinatorial sources, namely from characteristic pairs (Q, λ), where Q is a simple convex n-polytope and λ a labelling of its facets, and from ndimensional fans Σ. In the literature, they are referred as toric orbifolds and singular toric varieties respectively. Our first main result provides combinatorial conditions on (Q, λ) or on Σ which ensure that the integral cohomology groups H * (X) of the associated orbifolds are concentrated in even degrees. Our second main result assumes these condition to be true, and expresses the graded ring H * (X) as a quotient of an algebra of polynomials that satisfy an integrality condition arising from the underlying combinatorial data. Also, we compute several examples.

An iron-catalyzed intramolecular alkyne-aldehyde metathesis strategy of the alkynyl ether of salicylaldehyde derivatives has been developed which works under mild reaction conditions to produce the functionalized 2H-chromene derivatives. This protocol is compatible toward a wide range of functional groups, such as methoxy, fluoro, chloro, bromo, and phenyl groups. This method provides an atom-economical and environmentally friendly approach for the synthesis of a series of substituted 2H-chromenes.

An efficient and simple strategy has been developed to synthesize various substituted nitroalkenes involving a cooperative catalytic system of FeCl3 and piperidine. This dual catalytic protocol simultaneously activates both electrophile and nucleophile and works under mild reaction conditions so that many sensitive functional groups were tolerated. Moreover, this cooperative catalytic reaction is also suitable for various one‐pot reactions involving nitroalkenes such as, 2H‐chromenes, N‐arylpyrrole and Michael reaction with indole. Notably, this method is low‐cost, efficient and environmentally friendly.

An efficient synthesis of functionalized phenanthrenes has been developed for the first time involving an iron(III)-catalyzed intramolecular coupling of 2'-alkynyl-biphenyl-2-carbaldehydes. A broad range of functionalized phenanthrene derivatives could be obtained in the present method in moderate to good yields with high chemo- and regioselectivity. This transformation can also be applied to the synthesis of an angularly fused tetracyclic compound. This method offers several advantages such as high selectivity, mild reaction conditions, and easy availability of starting materials.

A new and efficient protocol to synthesize substituted benzo[b]carbazole derivatives has been demonstrated involving iron-catalyzed domino isomerization/cyclodehydration sequences from substituted 2-[(indoline-3-ylidene)(methyl)]benzaldehyde derivatives. The substrates could be easily made via Pd-catalyzed domino Heck-Suzuki coupling from 2-bromo-N-propargylanilide derivatives in high yields. Notably, the generality and efficiency of this two-stage domino strategy was further exemplified by the synthesis of a polycyclic benzofuran derivative.

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