Boron-Selective Biaryl Coupling Approach to Versatile Dibenzoxaborins and Application to Concise Synthesis of Defucogilvocarcin M
摘要:
An efficient synthetic method for versatile dibenzoxaborins based on boron-selective Suzuki-Miyaura cross-coupling between o-borylphenols and aryl halides or triflates bearing a 1,8-diaminonaphthalene-protected o-boryl group is reported. A short synthesis of defucogilvocarcin M was achieved using the proposed method in combination with several other boron-mediated transformations.
A facile method for preparing diverse aryne–nickel complexesfrom readily synthesized ortho-borylaryl triflates is described. Exploratory synthetic applications, including the synthesis of 1,2-difunctionalized arenes, based on the nucleophilic character of the aryne–nickel complexes are also demonstrated.
Generation of Arynes via Ate Complexes of Arylboronic Esters with an <i>ortho</i>-Leaving Group
作者:Yuto Sumida、Tomoe Kato、Takamitsu Hosoya
DOI:10.1021/ol401140d
日期:2013.6.7
An efficient method of generating aryne has been achieved by treating ortho-(trifluoromethanesulfonyloxy)arylboronic acid pinacol ester with tert-or sec-butyllithium. Monitoring the reaction by B-11 NMR has indicated that a boron-ate complex formed in situ is the eventual precursor that converts into aryne near room temperature. The prior formation of the ate complex at a low temperature has enabled us to use various arynophiles, including those bearing base-sensitive groups. The ready availability of the aryne precursors and mutual orthogonality in aryne generation with widely used ortho-silylaryl triflate have enhanced the utility of the method.