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
Mukaiyama aldol and Michael reactions catalyzed by lanthanide iodides
作者:Nicolas Giuseppone、Pierre Van de Weghe、Mohamed Mellah、Jacqueline Collin
DOI:10.1016/s0040-4020(98)00791-1
日期:1998.10
Samariumdiiodide is an efficient catalyst precursor which allows the formation of condensation products between various carbonylcompounds and ketene silyl acetals or enoxysilanes. With α,β-unsaturated carbonylcompounds, 1,2- or 1,4-additions are observed according to the structure of the substrate. α,β-Unsaturated ketones yield to enoxysilanes by selective Michael additions. Aldol poducts are isolated
new, simple and high-yield synthesis of a salt-free samarium(II) triflate, [Sm(OTf)2(DME)2] is described. In stoichiometric amounts this derivative mediates typical samarium (II) coupling reactions such as pinacolisation, dimerisation of imines and Barbier-type reactions. It can also acts as a precatalyst for Mukaiyama aldol and Michael reactions and Diels-Alder reactions.
Quaternary Ammonium Dendrimers as Lewis Base Catalysts for Mukaiyama–Aldol Reaction
作者:Tomoo Mizugaki、Casey E. Hetrick、Makoto Murata、Kohki Ebitani、Michael D. Amiridis、Kiyotomi Kaneda
DOI:10.1246/cl.2005.420
日期:2005.3
Surface-alkylated poly(propylene imine) dendrimer was treated with methyl iodide to afford quaternarized ammonium iodide dendrimer. The quaternarized dendrimer catalyzed the Mukaiyama–Aldol reaction of trimethylsilyl acetal with various aldehydes as a Lewis base in apolar toluene solvent.