TY  - JOUR
A1  - Jos, Swetha
A1  - Szwetkowski, Connor
A1  - Slebodnick, Carla
A1  - Ricker, Robert
A1  - Chan, Ka Lok
A1  - Chan, Wing Chun
A1  - Radius, Udo
A1  - Lin, Zhenyang
A1  - Marder, Todd B.
A1  - Santos, Webster L.
T1  - Transition Metal‐Free Regio‐ and Stereo‐Selective trans Hydroboration of 1,3‐Diynes: A Phosphine‐Catalyzed Access to (E)‐1‐Boryl‐1,3‐Enynes
JF  - Chemistry – A European Journal
N2  - 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.
KW  - enediyne
KW  - enyne
KW  - hydroboration
KW  - organocatalytic
KW  - stereoselective
Y1  - 2022
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-293784
VL  - 28
IS  - 63
ER  - 
TY  - THES
A1  - Ricker, Robert
T1  - Synthesis, group 10 metal-catalyzed cyclization reactions and hydroboration of polyynes
T1  - Synthese, Gruppe 10 metallkatalysierte Cyclisierungsreaktionen und Hydroborierung von Polyinen
N2  - 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.
N2  - Bisdiyne gehen eine Pd(0)-katalysierte Zyklisierung ein, bei der Azulen- und Naphthalinprodukte entstehen. Wenn Dibenzylidenaceton in der Reaktion vorhanden ist, kommt es zu einer [2+2+2]-Cyclisierung mit dem Bisdiin, wobei Cyclohexadien-Derivate entstehen. Ni(0) katalysiert die [2+2+2]-Cycloaddition von Diinen mit Tolanen zu alkinilierten o-Terphenylderivaten. Die D-A-substituierten Produkte sind solvatochrome, fluoreszierende Farbstoffe mit hohen Quantenausbeuten und kurzen Lebensdauern. Bis-Triarylboran-Tetrain-Farbstoffe wurden sowohl in neutraler als auch in tetrakationischer Form synthetisiert, die als DNA/RNA-Sensoren in Frage kommen. Beide Moleküle sind in Lösung schwach fluoreszierend und zeigen charakteristische Alkin-Absorptionen in den Raman-Spektren. Tributylphosphin katalysiert die trans-Hydroboration von 1,3-Butadinen mit HBpin. Mittels NMR- und HRMS-Experimenten haben wir experimentell bestätigt, dass der Phosphin-Angriff auf das Diin ein Schlüsselschritt im katalytischen Zyklus ist.
KW  - Polyine
KW  - Diine
KW  - Fluoreszierender Stoff
KW  - Übergangsmetall
KW  - group 10 element
KW  - cyclization reactions
KW  - fluorescence
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-286801
ER  -