[AlCl3 + 2THF]: A new and efficient catalytic system for Diels-Alder cycloaddition of α,β-unsaturated carbonyl compounds under solvent-free conditions
[AlCl3 + 2THF] is a new catalytic system for the Diels-Alder cycloaddition under SFC and air atmosphere. By using equimolar amounts of reactants, this catalyst prevents the polymerization of the diene and allows the corresponding adducts to be isolated with high regio- and stereocontrol and in excellent yields.
Fringuelli, Francesco,Girotti, Rugiada,Pizzo, Ferdinando,Vaccaro, Luigi
SuperQuat 5,5-dimethyl-4-iso-propyloxazolidin-2-one as a mimic of Evans 4-tert-butyloxazolidin-2-one
The incorporation of a gem-dimethyl group at the 5-position of a chiral oxazolidinone biases the conformation of the adjacent C(4)-stereodirecting group such that the gem-dimethyl-4-iso-propyl combination mimics a C(4)-tert-butyl group, providing higher levels of stereocontrol than a simple 4-iso-propyloxazolidinone. The generality of this principle is demonstrated with applications in stereoselective enolate alkylations, kinetic resolutions, Diels-Alder cycloadditions and Pd-catalysed asymmetric acetalisation reactions. The Royal Society of Chemistry 2006.
Bull, Steven D.,Davies, Stephen G.,Garner, A. Christopher,Kruchinin, Dennis,Key, Min-Suk,Roberts, Paul M.,Savory, Edward D.,Smith, Andrew D.,Thomson, James E.
p. 2945 - 2964
(2008/02/09)
Scandium(III) triflate/isopropyl-pybox complex as an efficient catalyst for asymmetric Diels-Alder reaction
The chiral scandium (III) triflate/i-Pr-pybox complex efficiently catalyzes the asymmetric Diels-Alder reaction of 1,3-dienes with acyl-1,3-oxazolidin-2-ones (1a-c) afford the corresponding adducts in good yields with up to 90% ee. The reaction can be car
Fukuzawa, Shin-Ichi,Matsuzawa, Hiroshi,Metoki, Ken
p. 709 - 711
(2007/10/03)
Scandium perfluoroalkanesulfonate-catalyzed Diels-Alder reactions in an organic solvent
Scandium perfluoroalkanesulfonate-catalyzed Diels-Alder reactions proceeded smoothly in dry dichloromethane in the presence of molecular sieves (MS) 5 ?. It was found that water interfered with the reactions, contrary to most rare earth-catalyzed reactions that proceed smoothly in aqueous media. Among scandium perfluoroalkanesulfonates tested, scandium triflate (Sc(OTf)3), scandium pentafluoroethanesulfonate (Sc(OSO2C2F5)3), and scandium nonafluorobutanesulfonate (Sc(OSO2C4F9)3) gave the highest yields and selectivities.
Scandium trifluoromethanesulfonate (Sc(OTf)3). A novel reusable catalyst in the Diels-Alder reaction
Scandium trifluoromethanesulfonate (Sc(OTf)3) is found to be quite effective as a Lewis acid catalyst in the Diels-Alder reaction. The novel catalyst is available in both aqueous and organic media, is easily recovered from aqueous layer after the reaction is completed, and can be reused.