Efficient AgOTf or Ph3PAuCl–AgSbF6 catalyzed cyclization of 1-hydroxy-2-alkynylallylphosphonates/2-alkynylallyl alcohols to 2-furylphosphonates/2,3,5-trisubstituted furans
摘要:
The reaction of 1-hydroxy-2-alkynylallylphosphonates, synthesized by the addition of the corresponding phosphites to 2-alkynylcinnamaldehydes, under AgOTf or Ph3PAuCl-AgSbF6 catalyzed cycloisomerization afforded 2-furylphosphonates in good to excellent yields. These cyclization reactions were compared with those of 2-alkynylallyl alcohols that led to multisubstituted furans. (C) 2012 Published by Elsevier Ltd.
Synthesis of furans and pyrroles via migratory and double migratory cycloisomerization reactions of homopropargylic aldehydes and imines
作者:Roohollah Kazem Shiroodi、Claudia I. Rivera Vera、Alexander S. Dudnik、Vladimir Gevorgyan
DOI:10.1016/j.tetlet.2015.01.006
日期:2015.6
A novel gold-catalyzed divergent synthesis of furans and pyrroles employing readily available homopropargylic aldehydes and imines has been developed. The regiochemical outcome of this reaction is dependent on the substituent on the terminal alkyne of substrate. Thus, substrates possessing alkyl and aryl substituent at the alkyne moiety produce 2,3,5-substituted furans and pyrroles via a migratory
Indium‐Catalysed Transfer Hydrogenation for the Reductive Cyclisation of 2‐Alkynyl Enones towards Trisubstituted Furans
作者:Luomo Li、Sascha Kail、Sebastian M. Weber、Gerhard Hilt
DOI:10.1002/anie.202109266
日期:2021.10.25
Indiumtribromidecatalysed the transferhydrogenation from dihydroaromatic compounds, such as the commercially available γ-terpinene, to enones, which resulted in the cyclisation to trisubstituted furan derivatives. The reaction was initiated by a Michael addition of a hydride nucleophile to the enone subunit followed by a Lewis-acid-assisted cyclisation and the formation of a furan–indium intermediate
三溴化铟催化从二氢芳香族化合物(例如市售的γ-萜品烯)到烯酮的转移氢化,从而环化为三取代的呋喃衍生物。该反应是通过将氢化物亲核试剂迈克尔加成到烯酮亚基上引发的,然后进行路易斯酸辅助环化并形成呋喃-铟中间体和衍生自二氢芳族起始材料的Wheland中间体。该产物是通过 Wheland 配合物质子化形成的,并取代了三溴化铟取代基。此外,二氢芳香族 HD 替代物的位点特异性氘标记导致了产物的位点特异性标记,并通过 H-D 加扰提供了对反应机制的有用见解。
Borane/Gold(I)‐Catalyzed C−H Functionalization Reactions and Cycloaddition Reactions of Amines and α‐Alkynylenones
作者:Jun‐Jie Tian、Wei Sun、Rui‐Rui Li、Gui‐Xiu Tian、Xiao‐Chen Wang
DOI:10.1002/anie.202208427
日期:2022.8.26
generated in situ from α-alkynylenones and gold catalysts were successfully used for borane-catalyzed amine C−H functionalization reactions, giving amine derivatives bearing a furan ring. The reactions took place either via an α-furylation pathway or via a [3+2] cycloaddition pathway, depending on the alkyl groups attached to the amine.