Etude des ortho-metallations regioselectives de la chloro-3 pyridine par des organolithiens et des amidures de lithium; effet d'orientation par le solvant, applications a la synthese
MARSAIS, F.;BREANT, P.;GINGUENE, A.;QUEGUINER, G., J. ORGANOMETAL. CHEM., 1981, 216, N 2, 139-147
作者:MARSAIS, F.、BREANT, P.、GINGUENE, A.、QUEGUINER, G.
DOI:——
日期:——
Hiyama Cross-Coupling of Chloro-, Fluoro-, and Methoxypyridyltrimethylsilanes: Room-Temperature Novel Access to Functional Bi(het)aryl
作者:Philippe Pierrat、Philippe Gros、Yves Fort
DOI:10.1021/ol047482u
日期:2005.2.1
pyridyltrimethylsilanes allowed us to perform efficient Hiyama cross-coupling with various (het)arylhalides. The reactions proceeded smoothly at room temperature leading to the corresponding functional bis(het)aryl in fair to excellent yields. The presence of pyridine nitrogen alpha to the trimethylsilyl group was requisite to achieve the cross-coupling. [Reaction: see text]
We have shown that the BuLi/LiDMAE reagent promotes the clean and regioselective C2 lithiation of 3- and 4-chloropyridines, while other reagents such as LDA or BuLi/TMEDA lead to classical ortho lithiation products or mixtures of regioisomers. The method was successfully applied to the preparation of various reactive 2,3- and 2,4-disubstituted pyridines.