Catalytic Selenium-Promoted Intermolecular Friedel–Crafts Alkylation with Simple Alkenes
作者:E Tang、Yinjiao Zhao、Wen Li、Weilin Wang、Meng Zhang、Xin Dai
DOI:10.1021/acs.orglett.5b03579
日期:2016.3.4
A method for conducting selenium-promoted intermolecular Friedel–Crafts (F–C) alkylation reactions has been developed with simple alkenes using trimethylsilyl trifluoromethanesulfonate as a catalyst and N-phenylselenophthalimide as an efficient selenium source. Electron-rich arenes smoothly underwent F–C alkylation with a variety of alkenes to afford alkylated products in good yield and with high regioselectivity
Relations between 77Se NMR chemical shifts of (phenylseleno)benzenes and their molecular structures derived from nine X-ray crystal structures
作者:Jette Oddershede、Lars Henriksen、Sine Larsen
DOI:10.1039/b211130f
日期:2003.3.13
An extensive library of 77Se chemical shifts have been generated from the NMR measurements on substituted (phenylseleno)benzenes, including 33 new compounds. The variation in chemical shifts cover 265 ppm ranging from 446 to 181 ppm.
Crystal structures have been determined for nine selected representatives of the substituted (phenylseleno)benzenes. The analysis of the crystal structures supported that through-space interactions between selenium and the ortho-substituent observed in the crystal structures also are likely to be present in solution.
The variation in the 77Se NMR chemical shifts can be rationalised from the intramolecular interactions with the substituent in the ortho-position. Furthermore it appears that these ortho-effects are roughly additive, and that it is the actual interactions and not the resulting conformational constraints that are responsible for the variations in the 77Se NMR chemical shifts.