title: Heteroatom-guided torquoselective olefination of alpha-oxy and alpha-amino ketones via ynolates.
abstract: Ynolates were found to react with alpha-alkoxy-, alpha-siloxy-, and alpha-aryloxyketones at room temperature to afford tetrasubstituted olefins with high Z selectivity. Since the geometrical selectivity was determined in the ring opening of the beta-lactone enolate intermediates, the torquoselectivity was controlled by the ethereal oxygen atoms. From experimental and theoretical studies, the high Z selectivity is induced by orbital and steric interactions rather than by chelation. In a similar manner, alpha-dialkylamino ketones provided olefins with excellent Z selectivity. These products can be easily converted into multisubstituted butenolides and gamma-butyrolactams in good yield.
authors.affiliation: Institute for Materials Chemistry and Engineering, Kyushu University, 6-1, Kasugakoen, Kasuga, Fukuoka 816-8580, Japan. shindo@cm.kyushu-u.ac.jp
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Shindo
authors.forename: Takashi
authors.initials: T
authors.lastname: Yoshikawa
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Itou
authors.forename: Seiji
authors.initials: S
authors.lastname: Mori
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nishii
authors.forename: Kozo
authors.initials: K
authors.lastname: Shishido
mesh_terms: D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000138:chemical synthesis; D000475:Alkenes / Q000737:chemistry*; D000588:Amines / Q000737:chemistry; D002625:Chemistry, Organic / Q000379:methods*; D007659:Ketones / Q000737:chemistry*
chemical_list: D000475:Alkenes; D000588:Amines; D007659:Ketones; C004511:butenolide; D015107:4-Butyrolactone