Enantioselective Rhodium-catalyzed C-C Bond Activation of Cyclobutanones
Abstract:
The activation of carbon-carbon bonds has attracted much attention in the past decade. Despite important progress, the development of asymmetric reactions lags behind. For the first time, asymmetric rhodium(I)-catalyzed direct oxidative additions into enantiotopic C-C bonds of cyclobutanones could be realized. Subsequent carboacylation of tethered olefins and carbonyl groups of the generated rhoda(III)cyclopentanone give an efficient access to complex polycyclic scaffolds in high yields. Despite operating at high reaction temperatures, the processes are characterized by outstanding enantioselectivities of generally greater than 99.5:0.5 er.
More Related Videos
10:42Preparation of N-2-alkoxyvinylsulfonamides from N-tosyl-1,2,3-triazoles and Subsequent Conversion to Substituted Phthalans and Phenethylamines
Published on: January 3, 2018
06:34Synthesis of Antiviral Tetrahydrocarbazole Derivatives by Photochemical and Acid-catalyzed C-H Functionalization via Intermediate Peroxides CHIPS
Published on: June 20, 2014
Related Concept Videos
Cyclohexenones via Michael Addition and Aldol Condensation: The Robinson Annulation
Cycloaddition Reactions: MO Requirements for Photochemical Activation
Cycloaddition Reactions: MO Requirements for Thermal Activation
Cycloaddition Reactions: Overview
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.
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
