@phdthesis{Ricker2023, author = {Ricker, Robert}, title = {Synthesis, group 10 metal-catalyzed cyclization reactions and hydroboration of polyynes}, doi = {10.25972/OPUS-28680}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-286801}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {Bisdiynes undergo Pd(0)-catalyzed cyclization, forming azulene and naphthalene products. When dibenzylideneacetone is present in the reaction, it undergoes a [2+2+2] cyclization with the bisdiyne, forming cyclohexadiene derivatives. Ni(0) catalyzes the [2+2+2] cycloaddition of diynes with tolanes towards alkynylated o-terphenyl derivatives. The D-A substituted products are solvatochromic, fluorescent dyes with high quantum yields and short lifetimes. Bis-triarylborane tetrayne dyes were synthesized in both neutral and tetracationic forms, as potential DNA/RNA sensor. Both molecules are weakly fluorescent in solution and exhibit characteristic alkyne absorptions in the Raman spectra. Tributyl phosphine catalyzes the trans-hydroboration of 1,3-butadiynes with HBpin. We confirmed experimentally via NMR and HRMS experiments, that phosphine attack on the diyne is a key step in the catalytic cycle.}, subject = {Polyine}, language = {en} } @article{JosSzwetkowskiSlebodnicketal.2022, author = {Jos, Swetha and Szwetkowski, Connor and Slebodnick, Carla and Ricker, Robert and Chan, Ka Lok and Chan, Wing Chun and Radius, Udo and Lin, Zhenyang and Marder, Todd B. and Santos, Webster L.}, title = {Transition Metal-Free Regio- and Stereo-Selective trans Hydroboration of 1,3-Diynes: A Phosphine-Catalyzed Access to (E)-1-Boryl-1,3-Enynes}, series = {Chemistry - A European Journal}, volume = {28}, journal = {Chemistry - A European Journal}, number = {63}, doi = {10.1002/chem.202202349}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-293784}, year = {2022}, abstract = {We report a transition metal-free, regio- and stereo-selective, phosphine-catalyzed method for the trans hydroboration of 1,3-diynes with pinacolborane that affords (E)-1-boryl-1,3-enynes. The reaction proceeds with excellent selectivity for boron addition to the external carbon of the 1,3-diyne framework as unambiguously established by NMR and X-ray crystallographic studies. The reaction displays a broad substrate scope including unsymmetrical diynes to generate products in high yield (up to 95 \%). Experimental and theoretical studies suggest that phosphine attack on the alkyne is a key process in the catalytic cycle.}, language = {en} }