Exposure of a mixture of propargyl vinyl ketone and a nucleophilic primary or secondary amine to activated dry silica gel in the absence of solvent leads to a cascade of reactions that results in the formation of an aminocyclopentenone. The reaction with triethylamine leads to a cross-conjugated cyclopentadienone.
Tandem alkylation–cyclization process via an O,C-dianion
摘要:
A general protocol for preparing densely functionalized cyclopentenones through a tandem nucleophilic addition-deprotonation-alkylation-cyclization process is described. Addition of lithioallene 2 to enamides 1 generates tetrahedral intermediate 3. Deprotonation of the gamma carbon atom of the allene function in situ, followed by trapping by a suitable electrophile and cyclization during workup leads to C6 substituted cyclopentenones 6. (c) 2005 Elsevier Ltd. All rights reserved.
作者:William I. Nicholson、Fabien Barreteau、Jamie A. Leitch、Riley Payne、Ian Priestley、Edouard Godineau、Claudio Battilocchio、Duncan L. Browne
DOI:10.1002/anie.202106412
日期:2021.9.27
The direct mechanochemical amidation of esters by ball milling is described. The operationally simple procedure requires an ester, an amine, and substoichiometric KOtBu and was used to prepare a large and diverse library of 78 amide structures with modest to excellent efficiency. Heteroaromatic and heterocyclic components are specifically shown to be amenable to this mechanochemical protocol. This
Nickel-Catalyzed Amide Bond Formation from Methyl Esters
作者:Taoufik Ben Halima、Jeanne Masson-Makdissi、Stephen G. Newman
DOI:10.1002/anie.201808560
日期:2018.9.24
reactions, the synthesis of amide bonds is accomplished primarily by wasteful methods that proceed by stoichiometric activation of one of the starting materials. We report a nickel‐catalyzed procedure that can enable diverse amides to be synthesized from abundant methylester starting materials, producing only volatile alcohol as a stoichiometric waste product. In contrast to acid‐ and base‐mediated amidations
Asymmetric Cyclopentannelation. Chiral Auxiliary on the Allene
作者:Paul E. Harrington、Marcus A. Tius
DOI:10.1021/ol0001362
日期:2000.8.1
An enantioselective variant of the synthesis of cross-conjugated cyclopentenones, based on D-glucose-derived chiral auxiliaries, is described. Minor modification of the method makes it applicable to the preparation of both enantiomeric series of products. Both enantiomers of the key intermediate in our roseophilin synthesis have been prepared.
Cobalt-Catalyzed Reductive Carboxylation of α,β-Unsaturated Compounds with Carbon Dioxide
作者:Chika Hayashi、Takuo Hayashi、Tohru Yamada
DOI:10.1246/bcsj.20150043
日期:2015.6.15
The gaseous carbon dioxide incorporation reaction with α,β-unsaturated compounds was examined in the presence of a catalytic amount of bis(acetylacetonato)cobalt(II) and using diethylzinc as a redu...
在催化量的双(乙酰丙酮)钴 (II) 存在下,并使用二乙基锌作为还原剂,研究了气态二氧化碳与 α,β-不饱和化合物的掺入反应。
The First Example of Nazarov Reactions of Vinyl Cumulenyl Ketones
作者:Eric Leclerc、Marcus A. Tius
DOI:10.1021/ol034110x
日期:2003.4.1
[reaction: see text] alpha-Lithio cumulenyl ethers can be prepared in situ and converted to alpha-allenyl cyclopentenones. Isomerization of the product of one such reaction has led to a furanyl cyclopentenone, the core structure of nakadomarin A.