Generation of Arynes via Ate Complexes of Arylboronic Esters with an <i>ortho</i>-Leaving Group

An efficient method of generating aryne has been achieved by treating <i>ortho</i>-(trifluoromethanesulfonyloxy)arylboronic acid pinacol ester with <i>tert</i>- or <i>sec</i>-butyllithium. Monitoring the reaction by ¹¹B NMR has indicated that a boron-ate complex formed in situ is the eventual precursor that converts into aryne near room temperature. The prior formation of the ate complex at a low temperature has enabled us to use various arynophiles, including those bearing base-sensitive groups. The ready availability of the aryne precursors and mutual orthogonality in aryne generation with widely used <i>ortho</i>-silylaryl triflate have enhanced the utility of the method

Preparation of Aryne–Nickel Complexes from <i>ortho</i>-Borylaryl Triflates

A facile method for preparing diverse aryne–nickel complexes from readily synthesized <i>ortho</i>-borylaryl triflates is described. Exploratory synthetic applications, including the synthesis of 1,2-difunctionalized arenes, based on the nucleophilic character of the aryne–nickel complexes are also demonstrated

Palladium-Catalyzed Regio- and Stereoselective Hydrosilylation of Electron-Deficient Alkynes

Highly regio- and stereoselective hydrosilylation applicable to a broad range of electron-deficient alkynes has been established using palladium catalysis. The synthetic utility of the method has been demonstrated by further transformations of α-silylalkenes, particularly Hiyama coupling and stereoinverting iododesilylation followed by Suzuki–Miyaura coupling, which enables stereodivergent syntheses of α-arylenoates

Boron-Selective Biaryl Coupling Approach to Versatile Dibenzoxaborins and Application to Concise Synthesis of Defucogilvocarcin M

An efficient synthetic method for versatile dibenzoxaborins based on boron-selective Suzuki–Miyaura cross-coupling between <i>o</i>-borylphenols and aryl halides or triflates bearing a 1,8-diamino­naph­thalene-protected <i>o</i>-boryl group is reported. A short synthesis of defucogilvocarcin M was achieved using the proposed method in combination with several other boron-mediated transformations

Concise Synthesis of <i>v</i>‑Coelenterazines

A novel synthetic method for <i>v</i>-coelenterazine (<i>v</i>-CTZ), which is a vinylene-bridged analog of native CTZ with a large red-shifted luminescence property, is described. The synthesis was achieved in a concise way through the use of three sequential cross-coupling reactions and ring-closing metathesis (RCM). A newly synthesized C2-modified trifluoromethyl analog <i>cf3-v</i>-CTZ showed slightly more red-shifted luminescence than <i>v</i>-CTZ when it was used as a substrate for <i>Renilla</i> luciferases

Inhibition of luminescence activity of CTZ-utilizing luciferases with deaza-coelenterazine (daCTZ) analogs as inhibitors.

Inhibition of luminescence activity of CTZ-utilizing luciferases with deaza-coelenterazine (daCTZ) analogs as inhibitors.</p

Purification of QL-nanoKAZ from 800 mL of cultured <i>E</i>. <i>coli</i> cells using a Ni-chelate column.

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Statistics of data collection and structure refinement.

Statistics of data collection and structure refinement.</p

Expression of QL-nanoKAZ in the presence or absence of the secretory signal peptide sequence from <i>Gaussia</i> luciferase (GLsp) in CHO-K1 cells.

Expression of QL-nanoKAZ in the presence or absence of the secretory signal peptide sequence from Gaussia luciferase (GLsp) in CHO-K1 cells.</p