title: Lewis Acid-Promoted [2 + 1] Cycloaddition Reactions of a 1-Seleno-2-silylethene to 2-Phosphonoacrylates: Stereoselective Synthesis of a Novel Functionalized alpha-Aminocyclopropanephosphonic Acid.
abstract: Stereoselective SnCl(4)-promoted [2 + 1] cycloaddition reactions of 1-seleno-2-silylethene 1 with 2-phosphonoacrylates 2 lead to highly functionalized cyclopropanephosphonate esters 3 in high yields. The cyclopropane products 3 are potentially versatile starting materials for biologically important compounds. Stereoselective synthesis of a novel functionalized alpha-aminophosphonic acid derivative, an analogue of (Z)-2,3-methanohomoserine 13, from the cycloadduct 3b was achieved. Stereoselectivity in the [2 + 1] cycloaddition was explained by consideration of the structure of the 2-SnCl(4) complex.
authors.affiliation: Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8258, Japan.
authors.forename: Shoko
authors.initials: S
authors.lastname: Yamazaki
authors.forename: Takashi
authors.initials: T
authors.lastname: Takada
authors.forename: Tomomi
authors.initials: T
authors.lastname: Imanishi
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Moriguchi
authors.forename: Shinichi
authors.initials: S
authors.lastname: Yamabe