Disubstituted
2-pyrones and 2-pyridones were obtained by bifunctional
urea-catalyzed Michael addition/lactonization or lactamization followed
by a Hg(OAc)2- or Hg(OAc)2/DBU-mediated hydrolysis/decarboxylation/dehydrogenation
process. This one-pot two-stage protocol enabled the rapid synthesis
of 4,6-disubstituted 2-pyrones and 2-pyridones from dithiomalonate
and β,γ-unsaturated α-keto esters in practical yields
under mild reaction conditions. Additionally, the obtained 2-pyridones
were facilely transformed to 2,4,6-trisubstituted pyridines in excellent
yields.
New l-proline-derived bifunctional secondary
amine organocatalysts
were synthesized for enantioselective Michael reactions in water as
a solvent. Application of these catalysts in Michael additions provided
high yield (up to 97%) with high stereoselectivity (dr up to 99:1
and ee up to 99%). The effect of phenyl group at (R)-C6 in the catalyst was investigated and played a key
role in successful catalysis by density functional theory computational
calculations. The synthetic utility of this reaction was demonstrated
by the formal synthesis of Sch 50971, which is a novel histamine H3 receptor agonist.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.