Intramolecular Insertions into Unactivated C(sp<sup>3</sup>)–H Bonds by Oxidatively Generated β-Diketone-α-Gold Carbenes: Synthesis of Cyclopentanones
作者:Youliang Wang、Zhitong Zheng、Liming Zhang
DOI:10.1021/jacs.5b02280
日期:2015.4.29
Generation of reactive α-oxogold carbene intermediates via gold-catalyzed oxidation of alkynes has become an increasing versatile strategy of replacing hazardous diazo carbonyl compounds with benign and readily available alkynes in the development of efficient synthetic methods. However, one of the hallmarks of metal carbene/carbenoid chemistry, i.e., insertion into an unactivated C(sp(3))-H bond
The readily prepared 2,4-bisperfluorooctylphenyl butylselenide catalyzes the epoxidation of various olefins with hydrogen peroxide in a fluorous biphasic system. The catalyst is selectively soluble in perfluorinated solvents and can easily be recovered simply by phase separation. Furthermore, the catalyst can be reused several times without a decrease of yield and an increase of reaction time.
The use of neat BrCl in organic and inorganic chemistry is limited due to its gaseous aggregate state and especially its decomposition into Cl2 and Br2. The stabilization of BrCl in form of reactive ionic liquids via a novel in situsynthesis route shifts this equilibrium drastically to the BrCl side, which leads to safer and easier‐to‐handle interhalogenation reagents. Furthermore, the crystalline
Splitting of β-carotene in the sexual interaction of Phycomyces
作者:Silvia Polaino、M. Mar Herrador、Enrique Cerdá-Olmedo、Alejandro F. Barrero
DOI:10.1039/c0ob00321b
日期:——
Two new 7-carbon compounds, 1 and 2, have been found in the culture medium of Phycomyces blakesleeanus. A genetic test showed that they derive from β-carotene. These new molecules represent the missing link that proves that β-carotene is split into fragments of 18, 15 and 7 carbon fragments, each head of a separate family of apocarotenoids.