Biaryl formation using the suzuki protocol: Considerations of base, halide, and protecting group.
摘要:
The generation of aryl anions prior to quenching with a trialkyl borate has been shown to be sensitive to the composition of the aryl substrate. Aryl iodides containing remote benzyl ether substituents undergo trans-metallation with sec-BuLi to cleanly give the desired aryl anions whereas the corresponding bromides afford appreciable quantities of dianionic intermediates. The arylboronic acids derived from alkylation of these anions subsequently undergo a palladium mediated coupling with aryl halides to provide good yields of the desired biaryls. Copyright (C) 1996 Elsevier Science Ltd.
Stepwise Mechanism for the Bromination of Arenes by a Hypervalent Iodine Reagent
作者:Albert Granados、Alexandr Shafir、Ana Arrieta、Fernando P. Cossío、Adelina Vallribera
DOI:10.1021/acs.joc.9b02784
日期:2020.2.21
A mild, metal-free bromination method of arenes has been developed using the combination of bis(trifluoroacetoxy)iodobencene and trimethylsilyl bromide. In situ-formed dibromo(phenyl)-λ3-iodane (PhIBr2) is proposed as the reactive intermediate. This methodology using PIFA/TMSBr has been applied with success to a great number of substrates (25 examples). The treatment of mono-substituted activated arenes
Asymmetric Total Syntheses of (−)-Renieramycin M and G and (−)-Jorumycin Using Aziridine as a Lynchpin
作者:Yan-Chao Wu、Jieping Zhu
DOI:10.1021/ol9024919
日期:2009.12.3
By exploring the triple reactivity of two aziridines and double nucleophilicity of two aromatics, convergent and versatile syntheses of the above four natural products were developed.