versatile access to highly functionalized tetronic acids has been successfully achieved through the reaction of conjugated ynones with carbondioxide. In the presence of a base, the enolates generated from the ynones capture CO2 via a carbon–carbon bond-forming reaction, accompanied by a 5-exo-dig cyclization reaction of the resulting carboxylate to the alkyne, activated by a silver catalyst. The present
A stereoselective synthesis of anti-γ,δ-alkynyl- and -alkenyl-β-hydroxy-α-amino esters from tin(<scp>ii</scp>) enolates of glycinate
作者:Jonathan J. Gridley、Michael P. Coogan、David W. Knight、K. M. Abdul Malik、Christopher M. Sharland、Jirada Singkhonrat、Siân Williams
DOI:10.1039/b306291k
日期:——
Condensations between the tin(II) enolate 11 of ethyl N-tosylglycinate and conjugated ynals 12 and ynones 14 are highly diastereoselective, in favour of the anti-isomers 13 and 15; similar reactions of enals and enones 17 show lower but still useful levels of anti-stereoselectivity.
This paper describes the direct synthesis of pyrazoles fromesters that comprises two sequential reactions: tert-butoxide-assisted C-C(=O) coupling reaction to yield [small beta]-ketonitrile or [small alpha],[small beta]-alkynone intermediates, and condensation by hydrazine addition....
Fast and Efficient Continuous Flow Method for the Synthesis of Ynones and Pyrazoles
作者:Mohanraj Kandasamy、Balaji Ganesan、Min-Yuan Hung、Wei-Yu Lin
DOI:10.1002/ejoc.201900468
日期:2019.6.2
An efficientmethod for the synthesis of ynones and polysubstituted pyrazoles in a continuous flow system through the generation of activated lithium acetylide. This system serves as a powerful strategy for a rapid, easy, and transition metal free process performed under mild reaction conditions, which provides a better reagent controll compared to the available benchtop methods.