217433-39-1Relevant academic research and scientific papers
Palladium catalyzed regioselective β-acetonation-α-allylation of activated olefins in one shot
Shim, Jae-Goo,Nakamura, Hiroyuki,Yamamoto, Yoshinori
, p. 8470 - 8474 (1998)
The reaction of certain activated olefins 4 with allyl acetoacetate 5 in the presence of catalytic amounts of Pd(PPh3)4 (5 mol %) in THF at room temperature gave the corresponding β-acetonated α-allylated double addition products 6 regioselectively in good to excellent yields. The nature of the electron-withdrawing group in activated olefins affected significantly the reactivity of substrates; at least one of two electron-withdrawing groups of 4 should be a CN group. A proposed mechanism for this unprecedented three- component coupling reaction involves oxa-π-allyl-π-allylpalladium intermediate 3a (or its synthetic equivalents 3b-d). The in situ generation of activated olefins 4, from the aldehyde 11 and malononitrile 12, followed by the palladium-catalyzed reaction with allyl acetoacetate 5 also worked well, producing the corresponding three-component coupling products in good yields. Furthermore, allyltributylstannane 13 and α-chloro acetone 14 could be used as the α-allylation and β-acetonation components, respectively, instead of allyl acetoacetate 5. The scope and limitations of palladium- catalyzed regioselective β-acetonation-α-allylation reaction of activated olefins are described.
