Chemoselective Aldol Reaction of Silyl Enolates Catalyzed by MgI<sub>2</sub> Etherate
作者:Wei-Dong Z. Li、Xing-Xian Zhang
DOI:10.1021/ol026585e
日期:2002.10.1
Mukaiyama-type aldol coupling of typical silyl enolates 2-4 with aryl or vinyl aldehydes and acetals was realized in the presence of 1-5 mol % of MgI(2) etherate (1) in a mild, efficient, and highly chemoselective manner. Iodide counterion, weakly coordinating peripheral ethereal ligands (Et(2)O) of Mg(II), and a noncoordinating reactionmedia (i.e. CH(2)Cl(2)) are among the critical factors for the
Mischmetall, an alloy of the light lanthanides, has been used in a variety of organicreactions, either as a coreductant in samarium(II)-mediated reactions (Barbier and Grignard-type reactions, pinacoliccouplingreactions) or as the promoter of Reformatsky-type reactions. It has been also employed as the starting material for easy syntheses of lanthanide trihalides, the reactivity of which has been
Lewis Base-Catalysed Mukaiyama–Aldol Reaction of Trimethylsilyl Enolates with Aldehydes
作者:Xingxian Zhang、Junchen Shi、Shenghui Hu
DOI:10.3184/030823410x12733354109885
日期:2010.5
efficient Mukaiyama-type aldolreaction of three typical silyl enolates, such as 1-(trimethylsiloxy)-1-methoxy-2-methyl-2-propene, 1-phenyl-1-trimethylsilyloxyethene and 1, 2-bis(trimethylsiloxy)cyclobutene, with aryl aldehydes and α,β–unsaturated aldehydes catalysed by 5 mol% of Lewis base catalyst 4-O2NPhOMgI in dichloromethane is described. The reaction proceeds under mild reaction conditions in good