A Powerful Chiral Counteranion Motif for Asymmetric Catalysis
作者:Pilar García-García、Frank Lay、Patricia García-García、Constantinos Rabalakos、Benjamin List
DOI:10.1002/anie.200901768
日期:2009.6.2
Room to swing a cat: A chiral disulfonimide has been designed as a powerful new motif for asymmetriccatalysis. As a first illustration, a highly efficient and enantioselective Mukaiyama aldol reaction has been developed (see scheme). The actual catalyst is proposed to be an N‐silyl imide which is generated in situ.
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
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.
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
A cationic iridium complex [Ir(cod)2]SbF6 was found to be a new and efficient Lewis acid catalyst for Mukaiyama aldol and Mannich reactions. Aldehydes react smoothly with silyl enol ethers to give β-siloxy ketones in the presence of 0.5 mol % of [Ir(cod)2]SbF6. The reaction of N-alkyl arylaldimines with ketene silyl acetals in the presence of 5 mol % [Ir(cod)2]SbF6/P(OPh)3 gave β-amino esters. After