TiCl 4 joue 对 Mukaiyama 立体选择性反应的重要控制作用。L'acide de Lewis sert aussi bien de groupe dirigeant lasterochimie que d'activateur du groupe carbonyle。Une forte pression creee lastereoselectivite via un etat de transition bateau, tandis qu'une faible pression produit lastereoselectivite via un etat de transition chaise
Chemoselective aldol condensation in 5 mol dm−3 lithium perchlorate–nitromethane. A comparison with lithium perchlorate–diethyl ether medium
作者:R. Sudha、S. Sankararaman
DOI:10.1039/a900095j
日期:——
Aldol reactions of silyl enol ethers with aldehydes proceed in 5 mol dm–3 lithium perchlorate–nitromethane medium at ambient temperature. The reaction is highly chemoselective such that only aldehydes and cyclic ketones reacted while acyclic and aromatic ketones failed to react. The same reaction is not promoted in 5 mol dm–3 lithiumperchlorate–diethylether medium. The difference between these two