Gas-phase synthesis and reactivity of Cu+–benzyne complexes

Cu⁺–benzyne complexes bearing ligands (L) were synthesized and their addition reactivity was studied in the gas phase using electrospray ionization ion trap mass spectrometry.

Modular synthesis of bis- and tris-1,2,3-triazoles by permutable sequential azide–aryne and azide–alkyne cycloadditions

A new method for aryne generation enabled facile synthesis of diverse bis- and tris-1,2,3-triazoles.

o-Benzyne fragmentation and isomerization pathways: a CASPT2 study

The mechanism for the thermal fragmentation of o-benzyne to C₄H₂ + C₂H₂ and C₆H₂.

Gold-catalyzed cyclizations of cis-enediynes: insights into the nature of gold-aryne interactions

Golden aryne? Gold aryne complexes are inferred as transition states in dual gold-catalyzed cyclizations of cis-enediynes (see scheme; DCE = 1,2-dichloroethane). They are better described as ortho-aurophenyl cations, which react with weak nucleophiles and undergo facile intramolecular insertions into C(sp(3))-H bonds. Indanes, fused heteroarenes, and phenol derivatives are readily prepared using this method.

Generation of arynes via ate complexes of arylboronic esters with an ortho-leaving group

An efficient method of generating aryne has been achieved by treating ortho-(trifluoromethanesulfonyloxy)arylboronic acid pinacol ester with tert- or sec-butyllithium. Monitoring the reaction by (11)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 ortho-silylaryl triflate have enhanced the utility of the method.

"Meta elimination," a diagnostic fragmentation in mass spectrometry

The diagnostic value of the "ortho effect" for unknown identification by mass spectrometry is well known. Here, we report the existence of a novel "meta effect," which adds to the repertoire of useful mass spectrometric fragmentation mechanisms. For example, the meta-specific elimination pathway described in this report enables unequivocal identification of meta isomers from ortho and para isomers of carboxyanilides. The reaction follows a specific path to eliminate a molecule of meta-benzyne, from the anion produced after the initial decarboxylation of the precursor. Consequently, in the CID spectra of carboxyanilides, a peak for the (R-CO-NH)(-) anion is observed only for the meta isomers. For example, the peaks observed at m/z 58, 86, 120, 128, and 170 from acetamido-, butamido-, benzamido, heptamido-, and decanamido-benzoates, respectively, were specific only to the spectra of meta isomers.