25 research outputs found
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 <sup>11</sup>B 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-diaminoÂnaphÂthalene-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
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