Bimolecular reduction of carbon dioxide: double synthons for alkynes trifunctionalization

Carbon dioxide reduction, as a sustainable and versatile strategy for the access of chemical fuels, has attracted increasing attention and enormous efforts have been devoted to it in recent years. However, employing carbon dioxide as double synthons via bimolecular reduction remains challenging. Here, by leveraging the bimolecular reduction of carbon dioxide to carbonyl and methyl respectively, we describe a Pd-catalyzed trifunctionalization of alkynes with aryl iodide for the first time and showcase its advantages on the formation of various β-diketones and their application in the constructing of heterocyclic compounds with important biological activity, including pyrimidine, oxazole, pyrazole.

Trifunctionalization of Aryl Iodides with Two Distinct Nitrogen and Carbon Electrophiles by Palladium/Norbornene Catalysis

Main observation and conclusion Herein,we report a highly chemo-and regioselective vicinal trifunctionalization of aryl iodides by palladium/norbornene(Pd/NBE)catalysis.The key feature of this new method is the introduction of two distinct nitrogen and carbon electrophiles,with a large gap in reactivity,for ortho-unsubstituted aryl iodides via an intermolecular and intramolecular C―H functionalization,respectively.Eight types of ipso terminations can be coupled with both ortho-amination and ortho-alkylation,affording a variety of polysubstituted benzoheterocyclic scaffolds.Silicon-tethered substrates can lead to polyfucntional arenes via a single-step operation.Noteworthy,these products exhibit full-color-tunable strong fluorescence emissions with large Stokes shifts,and product 7r can serve as a fluorescent probe to specifically target lysosome in living cells.

Copper-Catalyzed 1,2,5-Trifunctionalization of Terminal Alkynes Using SR as a Transient Directing Group for Radical Translocation

The first Cu-catalyzed 1,2,5-trifunctionalization of abundant terminal alkynes is realized by merging hydrogen atom transfer and traceless directing strategy with SR as a transient group,delivering highly functionalized aldehydes in moderate to excellent yields with broad substrate scope.The synthetic utility of this method was demonstrated by the gram-scale reaction and downstream transformations of the resultant products.Given the high efficient installation of three different functional groups in a single reaction,it can serve as a very attractive method for rapidly assembling complex molecules from readily available starting materials.

Cu/Pd-catalyzed borocarbonylative trifunctionalization of alkynes and allenes:synthesis ofβ-geminal-diboryl ketones

Functionalized bisboryl compounds have recently emerged as a new class of synthetically useful building blocks in organic synthesis.Herein,we report an efficient strategy to synthesizeβ-geminal-diboryl ketones enabled by a Cu/Pd-catalyzed borocarbonylative trifunctionalization of readily available alkynes and allenes.This reaction promises to be a useful method for the synthesis of functionalizedβ-geminal-diboryl ketones with broad functional group tolerance.Mechanistic studies suggest that the reaction proceeds through borocarbonylation/hydroboration cascade of both alkynes and allenes.

Spin-multiplexed full-space trifunctional terahertz metasurface[Invited]

The widespread use of multifunctional metasurfaces has started to revolutionize conventional electromagnetic devices due to their unprecedented capabilities and exceedingly low losses.Specifically,geometric metasurfaces that utilize spatially varied single-celled elements to impart arbitrary phase modulation under circularly polarized(CP)waves have attracted more attention.However,the geometric phase has intrinsically opposite signs for two spins,resulting in locked and mirrored functionalities for the right-handed and left-handed CP beams.Additionally,the demonstrated geometric metasurfaces so far have been limited to operating in either transmission or reflection modes at a single wavelength.Here,we propose a double-layered metasurface composed of complementary elliptical and reversal ring resonator structures to achieve simultaneous and independent control of the reflection and transmission of CP waves at two independent terahertz frequencies,which integrates three functions of reflected beam deflection,reflected Bessel beam generation,and transmitted beam focusing on the whole space.The high efficiency and simple design of our metasurface will open new avenues for integrated terahertz metadevices with advanced functionalities.