Reactivity of aldehydes with semi-stabilised arsonium ylide anions: synthesis of terminal (e)-1,3-dienes.
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.
Habrant
Damien
D
Laboratoire de Synthèse Bio-Organique, UMR 7175/LC1-CNRS, Faculté de Pharmacie, Université Louis Pasteur, 74 Route du Rhin, BP 24, 67401 Illkirch, France.
Stengel
Bruno
B
Meunier
Stéphane
S
Mioskowski
Charles
C
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
D000447:Aldehydes; D000475:Alkenes; D000838:Anions; D001152:Arsenicals