Related Experiment Video
Updated: Sep 19, 2025

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Cascade Grignard Addition: Propargyl Claisen Rearrangement for the Stereoselective Synthesis of α-Allene Quaternary
Estefania Armendariz-Gonzalez1, Adi Saputra1, Edward W Mureka1
1232 Choppin Hall, Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States.
None:
We report a new method for the enantio- and diastereoselective synthesis of α-allene quaternary centers in fully substituted cyclohexanones at the α-positions. This reaction involves asymmetric 1,2-carbonyl addition to 2-O-propargyl enones using a mixture of Grignard reagents and the PMP-H8-BINOL ligand. The resulting magnesium alkoxide chelate intermediate then activated the propargyl vinyl ether moiety, thereby triggering a cascade propargyl Claisen rearrangement in a diastereoselective manner. The synthetic applications of this method in the context of complex molecules are also demonstrated.
More Related Videos
10:17Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
07:36Versatile CO2 Transformations into Complex Products: A One-pot Two-step Strategy
Published on: November 9, 2019
Related Concept Videos
[3,3] Sigmatropic Rearrangement of Allyl Vinyl Ethers: Claisen Rearrangement
Cycloaddition Reactions: Overview
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Radical Anti-Markovnikov Addition to Alkenes: Overview
Acid Halides to Alcohols: Grignard Reaction
Grignard reagents are a source of carbanions and function as nucleophiles. The mechanism begins with the nucleophilic attack by the carbanion at the carbonyl carbon of the acid halide to form a tetrahedral intermediate. Next, the carbonyl group is re-formed, and the halide ion departs,...
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.