Development of Pharmaceutical Drugs, Drug Intermediates and Ingredients by Using Direct Organo-Click Reactions
作者:Dhevalapally B. Ramachary、Mamillapalli Kishor、Y. Vijayendar Reddy
DOI:10.1002/ejoc.200701014
日期:2008.2
two-carbon homologation through cascade O/H/H reactions of aldehydes 1, Meldrum's acid (3c), Hantzsch ester (4) and acetic acid/triethylamine in ethanol has been demonstrated. Additionally, we have developed a green synthesis of the highly substituted 1,2,3-triazole 17 from simple substrates through a two-step combination of olefination/hydrogenation/alkylation and Huisgen cycloaddition reaction sequences
The asymmetricallylicalkylation (AAA) reaction using less reactive, stable allylic sources is challenging. We achieved a nickel(0)-catalyzed AAA reaction of β-dicarbonyl compounds under ambient conditions through unstrained C–C bond activation of 2-allylated 2-methylcyclohexane-1,3-dione derivatives to afford the corresponding quaternary chiral compounds in high yield with high enantioselectivity
Asymmetric hydrogenation of esters through homogeneous catalysis is a significantly important transformation in organic synthesis. The systems developed so far mainly focused on chiral iridium and ruthenium catalysts, which required a base to facilitate the activity. Herein, we present a palladium-catalyzed asymmetric hydrogenation of lactones under base-free conditions through dynamic kinetic resolution
2-Phenylbenzimidazoline, generated in situ from ortho-phenylenediamine and benzaldehyde, is an effective reagent to achieve the chemoselective reduction of the styrenic double bond in 3-substituted coumarins, which takes place in high yield.