Ligand-Promoted <i>meta</i>-C–H Amination and Alkynylation
作者:Peng Wang、Gen-Cheng Li、Pankaj Jain、Marcus E. Farmer、Jian He、Peng-Xiang Shen、Jin-Quan Yu
DOI:10.1021/jacs.6b08942
日期:2016.10.26
Using a modified norbornene (methyl bicyclo[2.2.1]hept-2-ene-2-carboxylate) as a transient mediator, meta-C-H amination and meta-C-H alkynylation of aniline and phenol substrates have been developed for the first time. Both the identification of a monoprotected 3-amino-2-hydroxypyridine/pyridone-type ligand and the use of a modified norbornene as a mediator are crucial for the realization of these
for the preparation of 3-substituted isocoumarins via palladium-catalyzed nucleophilic addition/oxidative annulation of bromoalkynes with benzoic acids has been developed. Remarkably, preliminary mechanistic studies indicated that the transformation might proceed via a stereo- and regioselective nucleophilic addition and C–H functionalization procedure.
A novel method for the synthesis of α-amino alkenyl-substituted hydrazone derivatives was disclosed through silver-catalyzed reaction of sulfonyl hydrazones with ynamides. The present method features mild conditions, highstereoselectivity and good yields. The proposed mechanism involves silver-mediated generation of a keteniminium ion intermediate to facilitate the stereoselective addition of hydrazones
通过银催化磺酰与乙酰胺的反应,公开了一种合成α-氨基烯基取代的derivatives衍生物的新方法。本方法具有温和的条件,高的立体选择性和良好的收率。所提出的机理涉及银介导的酮亚胺离子中间体的产生,以促进在K 2 CO 3存在下立体选择性地添加,而在当前条件下不能构建吡唑环。
Pd-Catalyzed Regioselective C–H Alkenylation and Alkynylation of Allylic Alcohols with the Assistance of a Bidentate Phenanthroline Auxiliary
作者:Shibo Xu、Koji Hirano、Masahiro Miura
DOI:10.1021/acs.orglett.0c03444
日期:2020.11.20
A Pd-catalyzed regioselective C–H alkenylation of allylic alcohols with electron-deficient alkenes has been developed. The key to success is the introduction of bidentately coordinating phenanthroline directing group, which enables the otherwise challenging and regioselective C–H activation at the proximal alkenyl C–H bonds over the conceivably competitive allylic C–O bond activation. The same Pd/phenanthroline
Rhodium(III)‐Catalyzed Synthesis of Skipped Enynes via C(sp
<sup>3</sup>
)–H Alkynylation of Terminal Alkenes
作者:Franco Della‐Felice、Margherita Zanini、Xiaoming Jie、Eric Tan、Antonio M. Echavarren
DOI:10.1002/anie.202014877
日期:2021.3.8
The RhIII‐catalyzedallylicC−H alkynylation of non‐activated terminalalkenes leads selectively to linear 1,4‐enynes at room‐temperature. The catalytic system tolerates a wide range of functional groups without competing functionalization at other positions. Similarly, the vinylic C−H alkynylation of α,β‐ and β,γ‐ unsaturated amides gives conjugated Z‐1,3‐enynes and E‐enediynes.