22919-28-4Relevant articles and documents
Unveiling a Masked Polymer of Dewar Benzene Reveals trans-Poly(acetylene)
Seo, Jinwon,Lee, Stanfield Y.,Bielawski, Christopher W.
, p. 2923 - 2931 (2019/04/17)
A dibromo derivative of Dewar benzene, trans-5,6-dibromobicyclo[2.2.0]hex-1-ene, was polymerized using ring-opening metathesis polymerization (ROMP). The reaction proceeded in a controlled manner as changing the initial monomer-to-catalyst ratio afforded monodispersed polymers with tunable molecular weights and growing polymer chains were extended upon subsequent exposure to additional monomer. Treatment of the halogenated polymers with an alkyllithium reagent resulted in elimination followed by isomerization to afford trans-poly(acetylene). Based on a series of mechanistic and spectroscopic studies, the transformation was proposed to proceed through a cyclobutenyl intermediate that undergoes rearrangement. The methodology was found to be versatile as triblock copolymers containing the halogenated homopolymer were prepared and converted to their poly(acetylene)-containing derivatives. The polymers were characterized using gel permeation chromatography as well as a range of spectroscopic (NMR, FT-IR, UV-vis, and Raman) and analytical techniques.
SYNTHESIS OF 1,2-DISUBSTITUTED BENZENES AND BIPHENYLS FROM PHTHALIC ACIDS THROUGH ELECTROREDUCTION FOLLOWED BY ELECTROCYCLIC REACTIONS WITH ALKYNES
Ohno, Toshinobu,Ozaki, Masato,Inagaki, Atsuro,Hirashima, Tsuneaki,Nishiguchi, Ikuzo
, p. 2629 - 2632 (2007/10/02)
Various substituted 1,2-dihydrophthalic acids were synthesized by electroreduction of phthalic acids in excellent yields.The electrocyclic reaction of 1,2-dihydrophthalic acids or the methyl ester with alkynes gave 1,2-disubstituted benzenes and biphenyls in good yields together with fumaric acid or methyl fumarate.