title: Rhenium-catalyzed synthesis of 2H-1,2-oxaphosphorin 2-oxides via the regio- and stereoselective addition reaction of β-keto phosphonates with alkynes.
abstract: Treatment of β-keto phosphonates (Horner-Wadsworth-Emmons reagents) with terminal alkynes in the presence of a rhenium catalyst gave 2H-1,2-oxaphosphorin 2-oxides with various substitution patterns. The reaction proceeds via two consecutive processes: cleavage of a carbon-carbon σ-bond of the β-keto phosphonate with insertion of the alkyne in a regio- and stereoselective manner, followed by cyclization of the resulting δ-phosphonyl α,β-unsaturated ketone yielding the 2H-1,2-oxaphosphorin 2-oxide. Horner-Wadsworth-Emmons reagents were found to add to nonpolar unsaturated compounds under neutral conditions.
authors.affiliation: Division of Chemistry and Biotechnology, Graduate School of Natural Science and Technology, Okayama University , 3-1-1 Tsushimanaka, Kita-ku, Okayama 700-8530, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Murai
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nakamura
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Takai