Stereodivergent Synthesis of Trisubstituted Enamides: Direct Access to Both Pure Geometrical Isomers
作者:Luca Massaro、Jianping Yang、Suppachai Krajangsri、Emanuele Silvi、Thishana Singh、Pher G. Andersson
DOI:10.1021/acs.joc.9b01803
日期:2019.11.1
either (E)- or (Z)-isomers of trisubstituted enamides. Starting from an extensive range of ketones, it was possible to synthesize and isolate the desired pure isomer by switching the reaction conditions. Lewis acid activation enables the formation of the (E)-isomers in high stereoselectivity (>90:10) and good yields. On the other hand, the use of a Brønsted acid allows the preparation of the (Z)-isomers
The vicinal functionalization of N-alkoxyenamines, derived in situ from aldehydes and isoxazolidines, has been achieved with the formation of two new carbon–carbon bonds by utilizing an organo-aluminum reagent and subsequent allylmagnesium bromide or tributyltin cyanide as external carbon-centered nucleophiles. By changing the second carbon nucleophile, various amine derivatives were obtained in good
dyotropic rearrangement of α‐methylene‐β‐lactones has been realized, which enables the efficient access of a wide range of α‐methylene‐γ‐butyrolactones displaying remarkable structural diversity. Several appealing features of the reaction, including excellent efficiency, high stereospecificity, predictable chemoselectivity and broad substrate scope, render it a powerful tool for the synthesis of MBL‐containing
Triflic acid catalysed regioselective synthesis of substituted naphthalenes by benzannulation of carbonyls with alkynes
作者:Vanajakshi Gudla、Mokhamatam Sudheer、Chinthu Joginarayana Rao、Paul Douglas Sanasi、Venkateswara Rao Battula
DOI:10.1016/j.tet.2021.132214
日期:2021.6
An interesting and facile triflic acid catalysed annulation of α-aryl carbonyls with arylalkynes is presented for the regioselective synthesis of substitutednaphthalenes. The annulation reaction involves a sequence of electrophilic attack of carbonyl on arylalkyne and benzannulation catalysed by triflic acid. The present catalyst effects this transformation at room temperature itself. Intramolecular
Indole and indazole derivatives, for the treatment and prophylaxis of cerebral disorders, their preparation and their use
申请人:SANKYO COMPANY LIMITED
公开号:EP0562832A1
公开(公告)日:1993-09-29
Compounds of formula (I) :
[in which R¹ and R² are each hydrogen or various organic groups, p is 0, 1, 2 or 3, U is -CO- or -CH(OR³)- where R³ is hydrogen or a hydroxy-protecting group, V is an optionally unsaturated aliphatic hydrocarbon group and W is a nitrogen-containing group] are useful in the treatment and prophylaxis of dementia especially of the Alzheimer's type.