6533b870fe1ef96bd12d06a8
RESEARCH PRODUCT
Asymmetric Synthesis of Amino-Bis-Pyrazolone Derivatives via an Organocatalytic Mannich Reaction.
Anssi PeuronenUğur KayaPankaj ChauhanDieter EndersSuruchi MahajanKari Rissanensubject
Mannich reactions010405 organic chemistryChemistryOrganic Chemistryasymmetric synthesisSquaramideEnantioselective synthesisHalogenation010402 general chemistry01 natural sciencespyrazolones0104 chemical sciencesStereocenteramino-bis-pyrazolone productschemistry.chemical_compoundElectrophilePyrazolonesOrganic chemistryBifunctionalMannich reactionta116description
A new series of N-Boc ketimines derived from pyrazolin-5-ones have been used as electrophiles in asymmetric Mannich reactions with pyrazolones. The amino-bis-pyrazolone products are obtained in excellent yields and stereoselectivities by employing a very low loading of 1 mol % of a bifunctional squaramide organocatalyst. Depending on the substitution at position 4 of the pyrazolones, the new protocol allows for the generation of one or two tetrasubstituted stereocenters, including a one-pot version combing the Mannich reaction with a base-mediated halogenation. peerReviewed
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2017-01-01 | The Journal of organic chemistry |