182880-92-8Relevant academic research and scientific papers
Catalysis with inorganic cations. VI. The effect of chiral bis-oxazoline-magnesium perchlorate catalysts on chemo- and enantioselectivity of intramolecular Hetero Diels-Alder and ene reaction
Desimoni, Giovanni,Faita, Giuseppe,Righetti, PierPaolo,Sardone, Nicola
, p. 12019 - 12030 (1996)
(E)1-acetyl-[2-(3-methyl-2-butenyloxy)benzylidene]indolin-2-one (1) gives competition between the intramolecular Hetero Diels-Alder (HDA) (thermal conditions) and the intramolecular ene reaction (IER) (magnesium perchlorate - MP - catalyzed conditions). Several complexes derived from MP and chiral bis-oxazolines were found to be excellent chemo- and enantioselective catalysts with a different degree of selectivity depending on the substituents on the oxazoline ring. The most chemoselective oxazolinic ligand forced the reaction to give a ratio of [HDA]:[[IER] products 5:95. The trans-(4,5-diphenyloxazoline)-MP complex is the best enantioselective catalyst and the product of the IER of 1 can be prepared in 75% yield and 88% e.e..
