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
A mesoporous aluminosilicate (Al-MCM-41) was found to be an effective heterogeneous catalyst for the reaction of both aldehydes and acetals with silylenolethers or ketene silylacetals to give the corresponding aldol adducts in moderate to high yields. The remarkable high catalytic activity of Al-MCM-41 over amorphous silica-alumina and aluminum-free mesoporous silicate was observed in the reaction
A benzofuran-based cage-shaped borate showed a higher degree of Lewis acidity and exhibited photo-activated catalytic activity under black-light irradiation.
基于苯并呋喃的笼状硼酸盐显示出较高的路易斯酸度,并在黑光照射下表现出光活化的催化活性。
Diiodosamarium an excellent catalyst precursor for Aldolisation and Michael reactions.
作者:Pierre Van de Weghe、Jacqueline Collin
DOI:10.1016/s0040-4039(00)79253-7
日期:1993.6
SmI2 is the precursor of efficient catalysts for the aldolisationreactions of aldehydes and ketones with enol silanes. α,β-unsaturated ketones give 1,4-addidtions selectively.
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