title: Enantioselective addition of cyclic enol silyl ethers to 2-alkenoyl-pyridine-N-oxides catalysed by Cu(II)-bis(oxazoline) complexes.
abstract: Asymmetric reactions involving (E)-3-aryl-1-(pyridin-2-yl-N-oxide)prop-2-en-1-ones and cyclic enol silyl ethers show good yields and excellent enantioselectivities (up to 99.9 % ee) when catalysed by bis(oxazoline)-Cu(II)  complexes. Different reaction pathways can be followed by different enol silyl ethers: with 2-(trimethylsilyloxy)furan, a Mukaiyama-Michael adduct is obtained, whereas a hetero Diels-Alder cycloadduct was formed by using (1,2-dihydronaphthalen-4-yloxy)trimethylsilane. In the latter reaction, the absolute configuration of the product is consistent with a reagent approach to the less hindered Re face of the coordinated substrate in the reactive complex.
authors: Department of Organic Chemistry, University of Pavia, V. le Taramelli, 10; 27100 Pavia, Italy.
authors: Alessandro
authors: A
authors: Livieri
authors: Massimo
authors: M
authors: Boiocchi
authors: Giovanni
authors: G
authors: Desimoni
authors: Giuseppe
authors: G
authors: Faita
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D018360:Crystallography, X-Ray; D004988:Ethers, Cyclic / Q000737:chemistry*; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010080:Oxazoles / Q000737:chemistry*; D011725:Pyridines / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D004988:Ethers, Cyclic; D009942:Organometallic Compounds; D010080:Oxazoles; D011725:Pyridines; D003300:Copper; C013229:pyridine N-oxide