Related Experiment Video
Updated: Dec 29, 2025

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Enantio- and Diastereoselective Double Mannich Reaction between Ketones and Imines Catalyzed by Zn-ProPhenol
Barry M Trost1, Elumalai Gnanamani1
1Department of Chemistry , Stanford University , Stanford , California 94305 , United States.
Abstract:
Herein we present a Zn-ProPhenol-catalyzed double Mannich reaction between ynones and imines that generates 1,3-diamines in excellent yield as well as diastereo- and enantioselectivity (>99.5% ee). With 2.2 equiv of a single imine electrophile, we obtain pseudo-symmetrical diamines whereas, with two different imine partners, we obtain unsymmetrically substituted 1,3-diamines with three contiguous stereocenters. In addition, we showcase the utility of these double Mannich adducts by transforming the 1,3-diamine motif into a variety of interesting products.
More Related Videos
07:50Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
06:31Highly Stereoselective Synthesis of 1,6-Ketoesters Mediated by Ionic Liquids: A Three-component Reaction Enabling Rapid Access to a New Class of Low Molecular Weight Gelators
Published on: November 27, 2015
Related Concept Videos
α-Alkylation of Ketones via Enolate Ions
Aldehydes and Ketones with Amines: Imine and Enamine Formation Overview
Nitriles to Ketones: Grignard Reaction
The mechanism begins with a nucleophilic attack by the Grignard...
Aldehydes and Ketones with Amines: Imine Formation Mechanism
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Acid-Catalyzed α-Halogenation of Aldehydes and Ketones
In the first step of the mechanism, the acid protonates the carbonyl oxygen resulting in a resonance-stabilized cation, which subsequently loses an α-hydrogen to form an enol tautomer. The C=C bond in an enol is highly nucleophilic because of the electron-donating nature of the –OH group. Consequently, the double bond attacks an electrophilic halogen to form a...
Aldol Condensation with β-Diesters: Knoevenagel Condensation