7148-07-4Relevant articles and documents
Enamine Organocatalysts for the Thiol-Michael Addition Reaction and Cross-Linking Polymerizations
Sinha, Jasmine,Soars, Shafer,Bowman, Christopher N.
, p. 1693 - 1701 (2021/02/16)
This article describes an efficient enamine organocatalyzed thiol-Michael click reaction and its broad application in cross-linking polymerizations. A series of enamines was shown to catalyze the thiol-Michael reaction via a nucleophilic pathway. By varying the amines as well as the ring size of the ketones, enamines were designed with broad ranges of nucleophilic character ranging from 11 to 17 on the Mayr nucleophilicity scale. Upon evaluating the enamines' organocatalytic effect on the kinetics of reactions involving a thiol and Michael acceptor, wherein butyl 3-mercaptopropionate and 1-hexyl acrylate were used as model reactants, enamines were shown to outperform their base analogs. The efficiency and overall reaction yields, ranging from 11 to 92% based on the thiol conversion, were highly dependent upon the nucleophilicity of the enamines employed. Interestingly, in situ formation of an enamine via photo-deprotection of an amine in the presence of cyclic ketones facilitated the thiol-Michael reaction efficiently while simultaneously enabling higher functional group conversion. This efficiency in the reaction kinetics and conversion was extended to multifunctional derivatives, which resulted in the formation of highly cross-linked polymers.
1 microwave-induced montmorillonite-mediated facile synthesis of enamines
Yadav, Ram Naresh,Banik, Indrani,Srivastava, Ashok Kumar,Ramos, Katherine,Banik, Bimal Krishna
, p. 249 - 254 (2020/01/08)
Montmorillonite clay-mediated simple and high yielding protocol for the synthesis of various enamines with secondary amines and ketones is developed under microwave condition. This protocol is very convenient to accesses the enamines from cyclic amines with various carbonyl compounds in high yield under mild reaction conditions with short reaction time.
Preparation of Hexahydrocarbazole Derivatives by Reductive Indolization
Christoffers, Jens,Dierks, Anna,Fliegel, Lukas,Schmidtmann, Marc
, p. 7164 - 7175 (2020/11/30)
The reductive indolization is a two-step protocol performed in one flask: First, the acid-mediated Fischer indolization of a cyclic ketone with phenylhydrazine forms an iminium ion which is subsequently reduced by a hydrido borate reagent to the indoline as the final product. We utilized this new strategy for the preparation of hexahydrocarbazole derivatives with a side chain in the quaternary C4a-position. Starting materials were several N1- and aryl-substituted phenylhydrazines and a cyclic ketone with propanoic ester moiety, which is the product of the conjugated addition of cyclohexanone to ethyl acrylate. Furthermore, benzannulated congeners as well as a pyrido[4,3-b]indole derivative were accessed. The hexahydrocarbazole defines a molecular scaffold with two points of diversification. Therefore, several derivatives at N9 and at the C4a-side chain were prepared.
