A1 Refereed original research article in a scientific journal

Asymmetric Synthesis of Amino-Bis-Pyrazolone Derivatives via an Organocatalytic Mannich Reaction




AuthorsChauhan P, Mahajan S, Kaya U, Peuronen A, Rissanen K, Enders D

PublisherAMER CHEMICAL SOC

Publication year2017

JournalJournal of Organic Chemistry

Journal name in sourceJOURNAL OF ORGANIC CHEMISTRY

Journal acronymJ ORG CHEM

Volume82

Issue13

First page 7050

Last page7058

Number of pages9

ISSN0022-3263

DOIhttps://doi.org/10.1021/acs.joc.7b01113


Abstract
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 stereo-selectivities 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.



Last updated on 2024-26-11 at 10:29