Trimethylsilyl Trifluoromethanesulfonate- Accelerated Addition of Catalytically Generated Zinc Acetylides to Aldehydes
摘要:
In the presence of TMSOTf, a wide variety of terminal acetylenes add rapidly and efficiently to aldehydes via a catalytically generated zinc acetylide. In the absence of TMSOTf, no reaction is observed under otherwise identical conditions.
Electrochemically Enabled Intramolecular Aminooxygenation of Alkynes
<i>via</i>
Amidyl Radical Cyclization
作者:Zhong‐Wei Hou、Hai‐Chao Xu
DOI:10.1002/cjoc.201900500
日期:2020.4
An electrochemical synthesis of oxazol‐2‐ones and imidazol‐2‐ones has been developed via 5‐exo‐dig cyclization of propargylic carbamates‐ and ureas‐derived amidyl radicals. The electrosynthesis relies on the dual function of 2,2,6,6‐tetramethylpiperidin‐ 1‐yl)oxyl (TEMPO) as a redox mediator for amidyl radical formation and an oxygen atom donor. The reactions are conducted under mild conditions using
Formation of β-Oxo-<i>N</i>-vinylimidates via Intermolecular Ester Incorporation in Huisgen Cyclization/Carbene Cascade Reactions
作者:Qinxuan Wang、Jeremy A. May
DOI:10.1021/acs.orglett.0c03619
日期:2020.12.18
Unusual intermolecular trapping of esters by carbenes generated via a Huisgen cyclization/retroelectrocyclization/dediazotization cascadereaction is presented. β-Oxo-N-vinylimidates could be obtained in one step from propargyl carbonazidates. Mechanistic control experiments suggested reversible dipole formation by ester addition to the carbene, and nitrogen attack to the ester carbonyl was irreversibly
We have developed a unified strategy for preparing a variety of imidazo‐fused N‐heteroaromatic compoundsthrough regiospecific electrochemical (3+2) annulation reaction of heteroarylamines with tethered internal alkynes. The electrosynthesis employs a novel tetraarylhydrazine as the catalyst, has a broad substrate scope, and obviates the need for transition‐metal catalysts and oxidizing reagents.
Ti-catalyzed regioselective ring-opening alkynylation of epoxides with haloalkynes
作者:Di Zhang、Hao Li、Dong Yi、Shijing Tu、Zhongyu Qi、Siping Wei、Qiang Fu、Haiyan Fu、Xi Du
DOI:10.1016/j.tetlet.2021.153461
日期:2021.11
Ti-catalyzed ring-opening alkynylation of epoxides with haloalkynes has been achieved, allowing an efficient and regioselective entry to various propargylic alcohols in moderate to good yields. The developed protocol features extremely mild reaction conditions, broad substrate scope, varied functional group compatibility, and chemospecificity in the rearrangements of epoxides to aldehydes.
已经实现了环氧化物与卤代炔烃的 Ti 催化开环炔基化,允许以中等至良好的产率有效和区域选择性地进入各种炔丙醇。开发的协议具有极其温和的反应条件、广泛的底物范围、不同的官能团兼容性以及环氧化物重排为醛的化学特异性。