TfOH- and HBF<sub>4</sub>-Mediated Formal Cycloisomerizations and [4+3] Cycloadditions of Allene-alkynylbenzenes
作者:Yu Xiang、Zining Li、Lu-Ning Wang、Zhi-Xiang Yu
DOI:10.1021/acs.joc.8b00393
日期:2018.8.3
prepared allene-alkynylbenzenes to give pyrrolidines and cyclopentanes derivatives was developed. This reaction is initiated by the generation of allylic cation from allene, followed by alkyne’s reaction with the allylic cation, to give a vinylcation, which is finally intercepted by the triflate (TfO) anion. This cycloisomerization can be further tuned to become an acid-mediated intramolecular formal
Rh<sup>I</sup>-Catalyzed Cycloisomerization of Vinyl Bicyclopropyl Compounds to Azabicyclo[3.2.2]nona-2,8-dienes
作者:Sun Young Kim、Youn K. Kang、Young Keun Chung
DOI:10.1002/chem.200902284
日期:2010.5.10
Nitrogen‐containing heterobicycles are an important structural motif ubiquitous in natural alkaloids. We found that azabicyclo[3.2.2]nona‐2,8‐dienes can be synthesized from vinyl bicyclopropropyl derivatives in the presence of a RhI catalyst (see scheme). Syntheses of such compounds and an investigation into the reaction mechanism through DFT calculations are presented.
Copper‐Catalyzed Azide–Ynamide Cyclization to Generate α‐Imino Copper Carbenes: Divergent and Enantioselective Access to Polycyclic N‐Heterocycles
作者:Xin Liu、Ze‐Shu Wang、Tong‐Yi Zhai、Chen Luo、Yi‐Ping Zhang、Yang‐Bo Chen、Chao Deng、Rai‐Shung Liu、Long‐Wu Ye
DOI:10.1002/anie.202007206
日期:2020.10.5
Here an efficient copper‐catalyzed cascade cyclization of azide‐ynamides via α‐imino copper carbene intermediates is reported, representing the first generation of α‐imino copper carbenes from alkynes. This protocol enables the practical and divergent synthesis of an array of polycyclic N‐heterocycles in generally good to excellent yields with broad substrate scope and excellent diastereoselectivities
Gold(I)-Catalyzed 6-<i>endo</i>-Dig Hydrative Cyclization of an Alkyne-Tethered Ynamide: Access to 1,6-Dihydropyridin-2(3<i>H</i>)ones
作者:Nayan Ghosh、Sanatan Nayak、Akhila K. Sahoo
DOI:10.1002/chem.201301599
日期:2013.7.15
Hydrate your chemistry! Hydrativecyclization of 5‐yne‐ynamides in the presence of Echavarren's catalyst and p‐toluenesulphonic acid (PTSA)⋅H2O at room temperature affords an array of 1,6‐dihydropyridin‐2(3H)one derivatives. Isomerization, epoxidation, and hydrogenation of the double bond and insertion of an extended π‐conjugate system into the pyridinone skeleton have been successfully accomplished
Gold‐Catalyzed Annulations of
<i>N</i>
‐Propargyl Ynamides with Anthranils with Two Distinct Chemoselectivities
作者:Yu‐Chen Hsu、Shu‐An Hsieh、Rai‐Shung Liu
DOI:10.1002/chem.201806083
日期:2019.4.5
Gold‐catalyzedannulation of N‐propargyl ynamides with anthranils can proceed by two distinct mechanisms. In the case of a terminal N‐propargyl ynamide, its resulting α‐imino gold carbene reacts with a tethered alkyne to generate a vinyl cation to enable hydrolysis, which ultimately yields a pyrrolo[2,3‐b]quinoline derivative after treatment with p‐toluenesulfonic acid. For an internal alkyne, its
金催化的N-炔丙基乙酰胺与蒽的环化反应可以通过两种不同的机理进行。在末端N-炔丙基炔基酰胺的情况下,其生成的α-亚氨基金卡宾与链状炔反应生成乙烯基阳离子以实现水解,经p处理后最终生成吡咯并[2,3- b ]喹啉衍生物甲苯磺酸。对于内部炔烃,其α-亚氨基金卡宾通过乙烯基阳离子或烯基金卡宾与链状炔反应。两种途径最终都会导致生成4-酮-2-氨基吡咯衍生物。我们的机理分析表明,对于末端乙酰胺,水是比蒽乙更好的亲核试剂,而水和蒽甲对内部乙酰胺具有同等的反应性。