Next Article in Journal
Analysis of Targeted Metabolites and Molecular Structure of Starch to Understand the Effect of Glutinous Rice Paste on Kimchi Fermentation
Next Article in Special Issue
Recent Advances in the Addition of Amide/Sulfonamide Bonds to Alkynes
Previous Article in Journal
An Assessment of Computational Methods for Calculating Accurate Structures and Energies of Bio-Relevant Polysulfur/Selenium-Containing Compounds
Previous Article in Special Issue
Understanding the Exceptional Properties of Nitroacetamides in Water: A Computational Model Including the Solvent
Article Menu
Issue 12 (December) cover image

Export Article

Open AccessArticle

[2+2+2] Annulation of N-(1-Naphthyl)acetamide with Two Alkynoates via Cleavage of Adjacent C–H and C–N Bonds Catalyzed by an Electron-Deficient Rhodium(III) Complex

Department of Chemical Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo 152-8550, Japan
*
Authors to whom correspondence should be addressed.
Academic Editor: Michal Szostak
Molecules 2018, 23(12), 3325; https://doi.org/10.3390/molecules23123325
Received: 21 November 2018 / Revised: 7 December 2018 / Accepted: 12 December 2018 / Published: 14 December 2018
(This article belongs to the Special Issue Amide Bond Activation)
  |  
PDF [2616 KB, uploaded 18 December 2018]
  |  

Abstract

It has been established that an electron-deficient cationic CpE-rhodium(III) complex catalyzes the non-oxidative [2+2+2] annulation of N-(1-naphthyl)acetamide with two alkynoates via cleavage of the adjacent C–H and C–N bonds to give densely substituted phenanthrenes under mild conditions (at 40 °C under air). In this reaction, a dearomatized spiro compound was isolated, which may support the formation of a cationic spiro rhodacycle intermediate in the catalytic cycle. The use of N-(1-naphthyl)acetamide in place of acetanilide switched the reaction pathway from the oxidative [2+2+2] annulation-lactamization via C–H/C–H cleavage to the non-oxidative [2+2+2] annulation via C–H/C–N cleavage. This chemoselectivity switch may arise from stabilization of the carbocation in the above cationic spiro rhodacycle by the neighboring phenyl and acetylamino groups, resulting in the nucleophilic C–C bond formation followed by β-nitrogen elimination. View Full-Text
Keywords: alkynes; C–H bond cleavage; C–N bond cleavage; cyclopentadienyl complexes; N-(1-naphthyl)acetamide; rhodium; [2+2+2] annulation alkynes; C–H bond cleavage; C–N bond cleavage; cyclopentadienyl complexes; N-(1-naphthyl)acetamide; rhodium; [2+2+2] annulation
Figures

Graphical abstract

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

Supplementary material

SciFeed
Printed Edition Available!
A printed edition of this Special Issue is available here.

Share & Cite This Article

MDPI and ACS Style

Terasawa, J.; Shibata, Y.; Fukui, M.; Tanaka, K. [2+2+2] Annulation of N-(1-Naphthyl)acetamide with Two Alkynoates via Cleavage of Adjacent C–H and C–N Bonds Catalyzed by an Electron-Deficient Rhodium(III) Complex. Molecules 2018, 23, 3325.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Molecules EISSN 1420-3049 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top