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Reactivity of Aldehydes with Semi‐Stabilised Arsonium Ylide Anions: Synthesis of Terminal ( E )‐1,3‐Dienes
Author(s) -
Habrant Damien,
Stengel Bruno,
Meunier Stéphane,
Mioskowski Charles
Publication year - 2007
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200601549
Subject(s) - ylide , moiety , chemistry , reactivity (psychology) , bromide , halide , medicinal chemistry , prenylation , stereochemistry , organic chemistry , medicine , alternative medicine , pathology , enzyme
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 n BuLi 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≠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.