5072-70-8Relevant articles and documents
Rerouting and Improving Dauc-8-en-11-ol Synthase from Streptomyces venezuelae to a High Yielding Biocatalyst
Lauterbach, Lukas,Hou, Anwei,Dickschat, Jeroen S.
supporting information, p. 7923 - 7929 (2021/04/21)
The dauc-8-en-11-ol synthase from Streptomyces venezuelae was investigated for its catalytic activity towards alternative terpene precursors, specifically designed to enable new cyclisation pathways. Exchange of aromatic amino acid residues at the enzyme surface by site-directed mutagenesis led to a 4-fold increase of the yield in preparative scale incubations, which likely results from an increased enzyme stability instead of improved enzyme kinetics.
PhI(OAc)2-mediated alkoxyoxygenation of β,γ-unsaturated ketoximes: Preparation of isoxazolines bearing two contiguous tetrasubstituted carbons
Ye, Chenghao,Kou, Xuezhen,Yang, Guoqiang,Shen, Jiefeng,Zhang, Wanbin
supporting information, p. 1148 - 1152 (2019/03/26)
A PhI(OAc)2-promoted dioxygenation of allyl oximes, including one alkoxylation, has been developed. This reaction can give isoxazoline products bearing two contiguous tetrasubstituted carbons. Various oximes substrates bearing different aryl groups and tetrasubstituted-olefin moieties were compatible with the mild reaction conditions. A two-electron oxidation pathway was proposed based on results of preliminary mechanistic studies.
A Mechanistic Study of Halogen Addition and Photoelimination from π-Conjugated Tellurophenes
Carrera, Elisa I.,Lanterna, Anabel E.,Lough, Alan J.,Scaiano, Juan C.,Seferos, Dwight S.
supporting information, p. 2678 - 2689 (2016/03/12)
The ability to drive reactivity using visible light is of importance for many disciplines of chemistry and has significant implications for sustainable chemistry. Identifying photochemically active compounds and understanding photochemical mechanisms is important for the development of useful materials for synthesis and catalysis. Here we report a series of photoactive diphenyltellurophene compounds bearing electron-withdrawing and electron-donating substituents synthesized by alkyne coupling/ring closing or palladium-catalyzed ipso-arylation chemistry. The redox chemistry of these compounds was studied with respect to oxidative addition and photoelimination of bromine, which is of importance for energy storage reactions involving X2. The oxidative addition reaction mechanism was studied using density functional theory, the results of which support a three-step mechanism involving the formation of an initial η1 association complex, a monobrominated intermediate, and finally the dibrominated product. All of the tellurophene derivatives undergo photoreduction using 430, 447, or 617 nm light depending on the absorption properties of the compound. Compounds bearing electron-withdrawing substituents have the highest photochemical quantum efficiencies in the presence of an alkene trap, with efficiencies of up to 42.4% for a pentafluorophenyl-functionalized tellurophene. The photoelimination reaction was studied in detail through bromine trapping experiments and laser flash photolysis, and a mechanism is proposed. The photoreaction, which occurs by release of bromine radicals, is competitive with intersystem crossing to the triplet state of the brominated species, as evidenced by the formation of singlet oxygen. These findings should be useful for the design of new photochemically active compounds supported by main-group elements.
