Effets du solvant et du complexant sur la regioselectivite de la metallation. Cas de la (furyl-2)-2 pyridine
作者:P. Ribéreau、G. Quéguiner
DOI:10.1016/s0040-4020(01)88670-1
日期:1983.1
Lithiation of 2-(2-furyl)pyridine with n-butyllithium is dependent upon the nature of the solvent, lithium complexant, and temperature. ω-Lithiation of the furan ring increases with the importance of the solvation of the lithium atom (TMEDA > THF > ether > hexane). The α substituted derivative, which is the thermodynamically controlled product, is obtained in ether with a good yield either with DABCO-BuLi
Organoboron compounds are described that upon exposure to light absorb light and isomerize and form a dark-colored isomer. The dark-colored isomer converts back to the colorless isomer upon removal of light, or exposure to oxygen or heat. Such compounds can be added into polymeric matrices such as films. These compounds are suitable for UV-blocking, UV-detecting, and for oxygen-sensing applications. Uses include UV-blocking windows, sunglasses, and as indicators in packaging such as food packaging.