Nickel(II)-Catalyzed [3 + 2] Cycloaddition of Nitrones and Allenoates to Access <i>N</i>-Vinylindoles and <i>N</i>-Vinylpyrroles
作者:Pei-Pei Xu、Jun-Yi Liao、Jia-Jie Zhang、Wei-Min Shi、Cui Liang、Gui-Fa Su、Dong-Liang Mo
DOI:10.1021/acs.orglett.1c02695
日期:2021.10.1
A variety of N-vinylindoles and N-vinylpyrroles were prepared in moderate to good yields through the nickel(II)-catalyzed [3 + 2] cycloaddition of α,β-unsaturated nitrones with allenoates under mild reaction conditions. A rational mechanism for the formation of N-vinylindoles was proposed based on the 18O-labeled experiments and key intermediates detected by high-resolution mass spectrometry trace
在温和的反应条件下,通过镍 (II) 催化的 α,β-不饱和硝酮与烯丙酸酯的 [3 + 2] 环加成反应,以中等至良好的收率制备了多种N-乙烯基吲哚和N-乙烯基吡咯。基于18个O标记实验和高分辨率质谱痕量实验检测到的关键中间体,提出了N-乙烯基吲哚形成的合理机制。本方法突出了镍 (II) 控制的环化、原子经济反应、广泛的底物范围、良好的官能团耐受性和烯胺键的高 Z 立体选择性。
Synthesis of highly substituted oxetanes via [2+2] cycloaddition reactions of allenoates catalyzed by a guanidine Lewis base
作者:Philipp Selig、Aleksej Turočkin、William Raven
DOI:10.1039/c3cc40855h
日期:——
The first synthesis of highly substituted 3-alkyl-oxetan-2-ylidenes from allenoates was developed by using the bicyclic guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) as an exceptionally active nitrogen Lewis base catalyst.
Regio- and stereoselective copper-catalyzed β-borylation of allenoates by a preactivated diboron
作者:Steven B. Thorpe、Xi Guo、Webster L. Santos
DOI:10.1039/c0cc02270e
日期:——
A mild and efficient copper-catalyzed borylation of electron deficient allenoates using an sp2âsp3 mixed hybridized diboron regioselectively installs a boron moiety on the β-position with exclusive (Z)-double bond geometry.
Redox Isomerization/(3+2) Allenoate Annulation by Auto‐Tandem Phosphine Catalysis
作者:Jeremy T. Maddigan‐Wyatt、Mitchell T. Blyth、Jhi Ametovski、Michelle L. Coote、Joel F. Hooper、David W. Lupton
DOI:10.1002/chem.202103224
日期:2021.11.22
mediates the redox isomerization of amino crotonates to give imines which then undergo (3+2) annulation with a range of allenoates in a second phosphine catalyzed process. Computational studies indicate that pivotal to the success of this reaction is the use of catalysts with similar ability to add to both allenoate and crotonate.
Manganese‐Catalyzed C−H Functionalizations: Hydroarylations and Alkenylations Involving an Unexpected Heteroaryl Shift
作者:Chengming Wang、Ai Wang、Magnus Rueping
DOI:10.1002/anie.201704682
日期:2017.8.7
A manganese-catalyzed regio- and stereoselective hydroarylation of allenes is reported. The C−H functionalization method provides access to various alkenylated indoles in excellent yields. Moreover, a hydroarylation/cyclization cascade involving an unexpected C−N bond cleavage and aryl shift has been developed, which provides a new synthetic approach to substituted pyrroloindolones.