Metal-free visible-light-promoted C(sp<sup>3</sup>)–H functionalization of aliphatic cyclic ethers using trace O<sub>2</sub>
作者:Ben Niu、Bryan G. Blackburn、Krishnakumar Sachidanandan、Maria Victoria Cooke、Sébastien Laulhé
DOI:10.1039/d1gc03482k
日期:——
Presented is a light-promoted C–C bond forming reaction yielding sulfone and phosphate derivatives at room temperature in the absence of metals or photoredox catalyst. This transformation proceeds in neat conditions through an auto-oxidationmechanism which is maintained through the leaching of trace amounts of O2 as sole green oxidant.
Synthesis of Side-Chain Unsaturated<i>endo</i>- and<i>exo</i>-Brevicomins. Representatives of Pheromone Analogs in the Dioxabicyclo[3.2.1]octane Series
作者:Stefan Wershofen、H. -D. Scharf
DOI:10.1055/s-1988-27729
日期:——
The title substances endo- and exo-9 were synthesized via selective trans- and cis-opening of the epoxy tosylate 3, respectively. The tosylate 3 is easily obtainable from pentadienol 1.
Lipase-catalyzed resolution of stereogenic centers in steroid side chains by transesterification in organic solvents: the case of a 26-hydroxycholesterol
(PCL) lipase selectively catalyzes the acylation of the (25S)-isomer of the (25R,S)-26-hydroxycholesterol 1a when the transesterification is irreversibly carried out with vinyl acetate in a mixture of organic solvents (chloroform/tetrahydrofuran).