41825-83-6Relevant academic research and scientific papers
Annulated and bridged tetrahydrofurans from alkenoxyl radical cyclization
Schur, Christine,Kelm, Harald,Gottwald, Thomas,Ludwig, Arne,Kneuer, Rainer,Hartung, Jens
supporting information, p. 8288 - 8307 (2015/01/09)
4-Pentenoxyl radicals sharing two or more carbon atoms with a cycloalkane cyclize in a predictable manner stereoselectively and regioselectively to afford in solutions of bromotrichloromethane cycloalkyl-fused or -bridged 2-bromomethyltetrahydrofurans in up to 95% yield. Stereoselectivity in alkenoxyl radical ring closures arises from cumulative steric effects. The substituent positioned the closest to the alkene carbon, which is being attacked by the oxygen radical, exerts the strongest stereodirecting effect. This principal inductor guides 5-exo-cyclization 2,3-trans- or 2,4-cis-selectively. The substituent located further from the attacked π-bond is the secondary inductor. A secondary inductor in the relative trans-configuration enhances stereodifferentiation by the primary inductor; a cis-configured secondary inductor decreases this effect. A secondary inductor is not able to overrule the guiding effect of a similar sized primary inductor. Intramolecular 4-pentenoxyl radical additions to a cyclohexene-bound exo-methylene group or to endocyclic double bonds proceed cis-specifically, as exemplified by synthesis of a diastereomerically pure bromobicyclo[2.2.1]heptyl-annulated tetrahydrofuran from the verbenylethyloxyl radical. According to theory, the experimental 2,3-cis-specificity in alkoxyl radical cyclization to an endocyclic π-bond arises from strain associated with the 2,3-trans-ring closure. This journal is
Copper(I) Catalysis of Olefin Photoreactions. 10. Synthesis of Multicyclic Carbon Networks by Photobicyclization
Salomon, Robert G.,Ghosh, Subrata,Zagorski, Michael G.,Reitz, Michael
, p. 829 - 836 (2007/10/02)
The synthetic utility of copper-catalyzed photobicyclization for construction of tricyclic ring systems is explored.UV irradiation of several monocyclic β- and γ-(4-pentenyl)allyl alcohols in the presence of copper(I) trifluoromethanesulfonate (CuOTf) gen
