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
2-(2-呋喃基)吡啶与正丁基锂的锂化取决于溶剂的性质,锂络合剂和温度。呋喃环的ω-锂化反应随锂原子溶剂化的重要性而增加(TMEDA> THF>醚>己烷)。通过DABCO-BuLi或HMPT催化锂从ω到α位的迁移,可以在醚中以高收率获得作为热力学控制产物的α取代衍生物。此外,2-(2-呋喃基)和2-(2-噻吩基)吡啶的相对反应性表明氧,氮和硫原子的主要作用。