Related Experiment Video
Updated: Jul 4, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
A three-carbon (n+1+2) ring expansion method for the synthesis of macrocyclic enones. Application to muscone
Ihsan Erden1, Weiguo Cao, Mary Price
1San Francisco State University, Department of Chemistry and Biochemistry, 1600 Holloway Avenue, San Francisco, CA 94132, USA.
Abstract:
The three-carbon ring expansion methodology commences with the preparation of a cyclic allene (C9, C11, C13), readily available from the corresponding cycloalkene via dibromocarbene addition and subsequent treatment with methyllithium. Dichloroketene addition to the cyclic allene regioselectively provides the [2+2] cycloadduct which is reductively dechlorinated with zinc in methanol. The resulting cyclobutanone is then catalytically hydrogenated; cyclobutanone ring opening is affected with trimethylsilyl iodide; immediate dehydroiodination of the resulting beta-iodocycloalkanone with diazabicycloundecane (DBU) provides the corresponding macrocyclic enone. The 15-membered enone was converted to dl,-muscone with (CH(3))(2)CuLi.
Related Concept Videos
Synthesis of α-Substituted Carbonyl Compounds: The Stork Enamine Reaction
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Acid-Catalyzed Ring-Opening of Epoxides
Conjugate Addition of Enolates: Michael Addition

![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)