- Highly enantioselective synthesis of isoquinuclidine by diels-alder reaction of 1,2-dihydropyridine utilizing chiral bisoxazoline-Cu(II) complex
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The enantioselective Diels-Alder (D-A) reaction between N-phenoxycarbonyl- or N-benzyloxycarbonyl-1,2-dihydropyridine (1a or 1b) and N(2)-acryloyl-N(1)-(1- naphthylmethyl)-5,5-dimethylpyrazolidin-3-one (2b) using (S,S)-bisoxazoline- Cu(II) catalyst (A, B, C or D) has been investigated. Utilizing (S,S)-t-Bu-bisoxazoline-Cu(II) catalyst C, the D-A reaction of 1a and 2 afforded the endo-(7S)-isoquinuclidines (3, 4 or 5) in good chemical yields with high enantioselectivity (up to 99% e.e.).
- Hutabarat, N.D.M. Romauli,Seki, Chigusa,Shimizu, Takashi,Hirama, Masafumi,Kohari, Yoshihito,Nakano, Hiroto,Uwai, Koji,Takano, Nobuhiro,Kwon, Eunsang,Matsuyama, Haruo
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p. 203 - 217
(2013/08/23)
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- Synthesis of non-symmetric bisoxazoline compounds. An easy way to reach tailored chiral ligands
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Bisoxazoline compounds have been used as chiral catalyst ligands in a wide variety of reactions. A great deal of effort has been aimed at the synthesis of C2-symmetric bisoxazolines but very few references exist for non-symmetric ones. As part of our studies into the possible usefulness of non-symmetric bisoxazolines, we report an easy method for the synthesis of bisoxazoline compounds bearing different substituents in each oxazoline ring.
- Garcia, Jose I.,Mayoral, Jose A.,Pires, Elisabet,Villalba, Isabel
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p. 2270 - 2275
(2007/10/03)
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- An efficient and general one-pot method for the synthesis of chiral bis(oxazoline) and pyridine bis(oxazoline) ligands
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An expeditious method for the synthesis of chiral box and pybox ligands is reported. The approach is based on a one-pot condensation reaction of chiral β-amino alcohols with a dinitrile using stoichiometric or catalytic amounts of zinc triflate. Yields gr
- Cornejo,Fraile,García,Gil,Martínez-Merino,Mayoral,Pires,Villalba
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p. 2321 - 2324
(2007/10/03)
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