title: The first synthesis of phosphonoacrolein. Application to Diels-Alder reaction as heterodiene.
abstract: The first synthesis of phosphonoacrolein 3 was made in quantitative yield by acidic treatment of beta-ethoxy-alpha-(methoxymethyl)vinylphosphonate 2, derived from a beta-ethoxy-alpha-phosphonovinyl anion and MOMCl. The phosphonoacrolein 3 easily underwent a hetero-Diels-Alder reaction with electron-rich alkenes 4a-f or alkynes 9a-c under mild conditions, and phosphono-substituted pyrans 5a-d, 6e,f or pyranopyrans 11a-c were obtained in good to excellent yields. The reaction of 3 with cyclopentadiene and cyclohexadiene led to mixtures of [2 + 4] and [4 + 2] cycloadducts 7a, 8a and 7b, 8b in modest yields. The cycloaddition reaction between 3 and pyranopyran 13 or dibromocarbene and 13 resulted in [4 + 2] or [2 + 1] cycloadducts 14 or 15 in good yields.
authors.affiliation: Department of Applied Chemistry, Kyushu Institute of Technology, Sensui-cho, Tobata, Kitakyushu 804-8550, Japan.
authors.forename: Sadayuki
authors.initials: S
authors.lastname: Arimori
authors.forename: Ryoji
authors.initials: R
authors.lastname: Kouno
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Okauchi
authors.forename: Toru
authors.initials: T
authors.lastname: Minami