Intramolecular Aryl Migration of Diaryliodonium Salts: Access to <i>ortho</i>
-Iodo Diaryl Ethers
作者:Huangguan Chen、Jianwei Han、Limin Wang
DOI:10.1002/anie.201806405
日期:2018.9.17
developed for the synthesis of ortho‐iodo diaryl ethers by intramolecular aryl migration. The reaction conditions are mild with a broad substrate scope. Mechanistic insight suggests a sulfonyl‐directed nucleophilic aromatic substitution pathway. Additionally, the product ortho‐iodo diaryl ethers serve as versatile synthons as demonstrated with several coupling reactions. Furthermore, a useful thyroxine analogue
Ligand-Regulated Palladium-Catalyzed Regiodivergent Hydroarylation of the Distal Double Bond of Allenamides with Aryl Boronic Acid
作者:Xin Du、Huan Zhao、Xinling Li、Lizhi Zhang、Yunhui Dong、Ping Wang、Daopeng Zhang、Qing Liu、Hui Liu
DOI:10.1021/acs.joc.1c01303
日期:2021.10.1
inducing excellent E selectivity and anti-Markovnikovselectivity. (2) A switch of regioselectivity to 1,2-Markovnikov hydroarylation was obtained using bidentate phosphine ligand (dppf or Xantphos). The formed coordination Intermediate II led to the N-tether away from the Intermediate II and at the trans position of aryl, resulting in excellent E selectivity and Markovnikov selectivity. Meanwhile, tentative
在钯 (II) 催化剂存在下,实现了烯酰胺远端双键与芳基硼酸的配体调节区域发散加氢芳基化,提供了各种具有优异 E 选择性和马尔科夫尼科夫/反马尔科夫尼科夫选择性的官能化烯酰胺。提出了两种可能的配位中间体负责区域发散的氢化芳基化:(1)配位中间体 I,提议通过 MeCN、远端双键、苯基与钯的配位形成,导致芳基远离中间体 I,诱导优异的 E 选择性和抗马尔科夫尼科夫选择性。(2) 区域选择性转换为 1,2- Markovnikov使用双齿膦配体(dppf 或 Xantphos)获得氢芳基化。形成的配位中间体 II导致 N-tether 远离中间体 II并位于芳基的反式位置,从而导致优异的 E 选择性和马尔可夫尼科夫选择性。同时,对机理的初步研究证明,这种加氢芳基化的氢源更可能是硼酸。芳基硼酸和钯催化剂之间的金属转移是这种转变的第一步。
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.
Boron-Selective Biaryl Coupling Approach to Versatile Dibenzoxaborins and Application to Concise Synthesis of Defucogilvocarcin M
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.