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An efficient Sonogashira coupling of a heterocyclic phosphonium salt with a terminal alkyne via C-P bond cleavage was developed. The reactions proceeded smoothly in the presence of palladium catalyst, copper(I) iodide, and

A Pd-catalyzed C–F bond alkynylation of polyfluoroalkyl ketones with terminal alkynes has been developed. The method gives access to a range of modular perfluoroalkyl- and alkynyl-substituted furan derivatives in moderate yields with high chemoselectivity and regioselectivity. The key to the success of the present cascade reaction mainly relies on the well-controlled sequence of functionalization and alkynylation of multiple C(sp3)–F bonds. Mechanistic studies showed that the reaction presumably proceeded through a chelation-assisted oxidative addition of Pd to the C–F bond.

A titanium(IV)-mediated ring-opening/dehydroxylative cross-coupling of diaryl-substituted methanols with a cyclopropanol derivative was developed. The reactions proceeded efficiently to provide synthetically useful γ,γ-diaryl esters in moderate to good yields, which could be applied to the functionalization of complex molecules derived from bioactive fenofibrate and isoxepac and the synthesis of a precursor of Zoloft.

The copper(II)-mediated ring opening/alkynylation of cyclopropanol by employing inexpensive and commercially available terminal alkyne is developed. The reactions proceeded efficiently to afford synthetically useful alk-4-yn-1-ones in moderate to good yields with good functional group tolerance. Control experiments showed that the reaction presumably proceeds via the formation of intermediates of copper homoenolate and/or alkynylcopper species.

In this paper, by taking de Sitter space-time as a thermodynamic system, we study the equivalent thermodynamic quantities of de Sitter black hole in massive gravity, and furthermore obtain the equivalent thermodynamic quantities of the space-time. Our results show that the entropy of this type of space-time takes the same form as that in Reissner-Nordstrom-de Sitter space-time, which lays a solid foundation for deeply understanding the universal thermodynamic characteristics of de Sitter space-time in the future. Moreover, our analysis indicates that the equivalent thermodynamic quantities and relevant parameters play a very important role, especially in the investigation of the stability and evolution of de Sitter space-time., Comment: 6 pages, 6 figures