title: Novel asymmetric oxy-michael addition reaction of the chiral ketones to the achiral gamma--or delta-hydroxy-alpha,beta-unsaturated carbonyl compounds.
abstract: A novel asymmetric oxy-Michael addition reaction was developed. In the presence of a catalytic amount of base, chiral ketones 1 and 2, derived from D-glucose and D-fructose, respectively, reacted with omega-hydroxy enones or enoates 3a-e, 17 and 21 to form the hemiacetal-derived alkoxide which underwent stereoselective intramolecular Michael addition to give cyclic acetals. Although the stereoselectivities in the formation of the five-membered acetal rings were modest, six-membered ring formation proceeded with high stereoselectivity and the utility of the reaction was demonstrated by a simple syntheses of natural products.
authors.affiliation: Department of Applied Biological Chemistry, The University of Tokyo, Tokyo 113-8657, Japan. ashuten@mail.ecc.u-tokyo.ac.jp
authors.forename: H
authors.initials: H
authors.lastname: Watanabe
authors.forename: K
authors.initials: K
authors.lastname: Machida
authors.forename: D
authors.initials: D
authors.lastname: Itoh
authors.forename: H
authors.initials: H
authors.lastname: Nagatsuka
authors.forename: T
authors.initials: T
authors.lastname: Kitahara
mesh_terms: D001685:Biological Factors / Q000138:chemical synthesis*; D007659:Ketones / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D001685:Biological Factors; D007659:Ketones