A Mechanism Switch in Enyne Metathesis Reactions Involving Rearrangement: Influence of Heteroatoms in the Propargylic Position
摘要:
Novel findings concerning the mechanism of enyne metathesis reactions involving rearrangement are presented. It has been demonstrated that the presence of either oxygen or nitrogen at the propargylic position leads to opposite regioselectivities in the presence of a cross-metathesis partner. The application of these reactions to domino processes is also described.
Radical Borylation/Cyclization Cascade of 1,6-Enynes for the Synthesis of Boron-Handled Hetero- and Carbocycles
作者:Shi-Chao Ren、Feng-Lian Zhang、Jing Qi、Yun-Shuai Huang、Ai-Qing Xu、Hong-Yi Yan、Yi-Feng Wang
DOI:10.1021/jacs.7b01889
日期:2017.5.3
construct boron-handled cyclic molecules was developed based on a radical borylation/cyclization cascade of 1,6-enynes. The process was initiated by the chemo- and regio-controlled addition of an N-heterocyclic carbene-boryl radical to an alkene or alkyne, followed by ring closure to afford boron-substituted cyclic skeletons. Further molecular transformations of the cyclic products to synthetically
Ruthenium-Catalyzed Ring-Opening and Ring-Closing Enyne Metathesis
作者:Tsuyoshi Kitamura、Miwako Mori
DOI:10.1021/ol015606m
日期:2001.4.1
a CH2Cl2 solution of an enyne containing the cycloalkene moiety was stirred in the presence of ruthenium-carbene complex (10 mol %) at room temperature under ethylene gas (1 atm), ring-opening and ring-closingmetathesis occurred to afford cyclized triene. The reaction was carried out under argon gas, and no cyclized product was obtained. Enynes with a terminal alkyne gave good results.
作者:Tsuyoshi Kitamura、Yuichi Kuzuba、Yoshihiro Sato、Hideaki Wakamatsu、Reiko Fujita、Miwako Mori
DOI:10.1016/j.tet.2004.05.030
日期:2004.8
Ring-opening metathesis and ring-closing metathesis (ROM-RCM) of cycloalkene-yne was demonstrated using a first- or second-generation ruthenium complex. When cycloalkenes bearing the alkyne part at the C-3 position were reacted with a first-generation ruthenium-carbene complex under an atmosphere of ethylene, ROM-RCM proceeded smoothly to give skeletal reorganized products in good yields. In this reaction, cycloalkene-ynes having terminal alkyne were suitable. On the other hand, when cycloalkenes bearing the alkyne part at the C-1 position were treated with a second-generation ruthenium-carbene complex, ROM-RCM proceeded smoothly to give bicyclic compounds and/or dimeric compounds in good yields. (C) 2004 Elsevier Ltd. All rights reserved.