71521-86-3Relevant academic research and scientific papers
A novel 1,2-migration of arylzincates bearing a leaving group at benzylic position: Application to a three-component coupling of p-iodobenzyl derivatives, trialkylzincates, and electrophiles leading to functionalized p- substituted benzenes
Harada, Toshiro,Kaneko, Takayuki,Fujiwara, Takayuki,Oku, Akira
, p. 9317 - 9332 (2007/10/03)
A three-component coupling of p-iodobenzyl derivatives, trialkylzincates, and electrophiles is described. Lithium trialkylzincates (R3ZnLi) react with p-iodobenzyl methanesulfonate to give benzylzinc reagents p-RC6H4CH2Zn(L). The reaction proceeds through a mechanism involving initial iodine/zinc exchange and the 1,2-migration of the resulting arylzincates. The benzylzinc reagents, thus prepared, are subsequently used in coupling reaction with electrophiles such as aldehydes, ketones, acyl chlorides, tosyl cyanide, and chlorosilanes to give a variety of functionalized p-substituted benzenes. Reactions under Barbier conditions in which the corresponding benzylzinc reagents are generated in the presence of electrophiles work well for Me3ZnLi and for magnesium zincates R3ZnMgBr derived from Grignard reagents. Generation of secondary benzylzinc reagents starting from diethyl 1-(p-iodophenyl)ethyl phosphate and their reaction with electrophiles are also achieved under Barbier conditions. Ketones, allyl bromides, and chlorosilanes are successfully used as electrophiles under these conditions.
Generation of allyl- and benzyllithiums from the corresponding halides by the aid of lithium-tellurium exchange reactions
Kanda, Takahiro,Kato, Shinzi,Sugino, Takushi,Kambe, Nobuaki,Sonoda, Noboru
, p. 71 - 84 (2007/10/02)
A variety of allyl- and benzyllithiums were prepared by lithium-tellurium exchange reactions of allylic and benzylic tellurides generated in situ from the corresponding halides.The produced organolithiums were trapped successfully with electrophiles such as aldehydes, ketones, and trimethylchlorosilane.Benzyllithiums having an alkyl, alkoxy,fluoro, chloro, or cyano substituent(s) on their aromatic ring were generated efficiently in THF.Benzylic tellurides bearing a bromo or iodo substituent afforded a mixture of products under similar conditions arising from the competing lithium-halogen exchange and/or the displacement of the halogen atom with organolithiums used, but they were converted selectively to benzyllithiums in ether without affecting halogen substituents on the benzene ring.Several allyllithiums including dilithioisobutene were generated from allylic halides in a similar way via allylic tellurides.Wurtz-type coupling was negligible in any reactions examined. Key words: Tellurium; Lithium; Allyl; Benzyl; Halide
METALATION REACTIONS. VII. METALATION OF BENZYLALKYL AND β-PHENETHYLALKYL SULFIDES
Cabiddu, S.,Floris, C.,Melis, S.,Piras, P. P.,Sotgiu, F.
, p. 149 - 156 (2007/10/02)
The products from the reaction between n-butyllithium and benzylalkyl and β-phenethylalkyl sulfides followed by carbonation, have been investigated by GLC/MS analysis.With benzylalkyl sulfides metalation occurs at the benzylic position, and the corresponding carboxylic acid can be isolated, but side products from Wittig like rearrangement, cleavage of the thioether bond, and aliphatic and aromatic substitution are also obtained.No benzylic metalation or Wittig-like rearrangement products are obtained from β-phenethyl sulfides: instead cleavage of the thioether bond and aliphatic and aromatic substitution occur.
