A1 Journal article – refereed
Asymmetric Synthesis of Amino-Bis-Pyrazolone Derivatives via an Organocatalytic Mannich Reaction

List of Authors: Chauhan P, Mahajan S, Kaya U, Peuronen A, Rissanen K, Enders D
Publication year: 2017
Journal: Journal of Organic Chemistry
Journal name in source: JOURNAL OF ORGANIC CHEMISTRY
Journal acronym: J ORG CHEM
Volume number: 82
Issue number: 13
Number of pages: 9
ISSN: 0022-3263

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 2019-20-07 at 04:39