title: Reactivity of aldehydes with semi-stabilised arsonium ylide anions: synthesis of terminal (e)-1,3-dienes.
abstract: A study of the reactivity of semi-stabilised arsonium ylide anions in olefination reactions is presented. The different ylide anions were generated by the addition of nBuLi to various arsonium halide derivatives: [Ph(2)As(R)R'](+)X(-), where R and R' are methyl, allyl, prenyl or benzyl groups. By using diallyldiphenylarsonium bromide (R=R'=allyl) an olefination protocol was optimised allowing the efficient transformation of aliphatic aldehydes into terminal 1,3-dienes with a high selectivity for the E isomer (E/Z ratios ranging from 90:10 to 97:3). The olefination reactions of aldehydes with dissymmetric arsonium halides (R not equal R') are very chemoselective; with arsonium ylide anions the benzyl moiety is more reactive than the allyl moiety which is much more reactive than prenyl and methyl groups. Based on the experimental results, a mechanism is proposed for the reaction.
authors.affiliation: Laboratoire de Synthèse Bio-Organique, UMR 7175/LC1-CNRS, Faculté de Pharmacie, Université Louis Pasteur, 74 Route du Rhin, BP 24, 67401 Illkirch, France.
authors.forename: Damien
authors.initials: D
authors.lastname: Habrant
authors.forename: Bruno
authors.initials: B
authors.lastname: Stengel
authors.forename: Stéphane
authors.initials: S
authors.lastname: Meunier
authors.forename: Charles
authors.initials: C
authors.lastname: Mioskowski
mesh_terms: D000447:Aldehydes / Q000737:chemistry*; D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry; D000838:Anions / Q000737:chemistry; D001152:Arsenicals / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D017550:Spectroscopy, Fourier Transform Infrared; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D000475:Alkenes; D000838:Anions; D001152:Arsenicals