Substrate‐Controlled and Site‐Selective [3+2] Cycloadditions of N‐Heterocyclic Carbene Derived Ambident Dipoles
- 4 May 2007
- journal article
- research article
- Published by Wiley in Chemistry – A European Journal
- Vol. 13 (15), 4282-4292
- https://doi.org/10.1002/chem.200601482
Abstract
2-Aryl thiocarbamoyl benzimidazolium and imidazolinium inner salts derived from benzimidazole and imidazoline carbenes are unique ambident C-C-S and C-C-N 1,3-dipolar systems, which undergo highly efficient and site-selective cycloaddition reactions with dimethyl acetylenedicarboxylate or dibenzoylacetylene to furnish spiro(imidazole-2,3′-thiophene) derivatives in excellent yields. When treated with ethyl propiolate, methyl acrylate or acrylonitrile, spiro(imidazole-2,3′-pyrrole) derivatives were formed in good yields. Theoretical studies revealed an asynchronous concerted mechanism for both the C-C-S and C-C-N 1,3-dipolar cycloaddition reactions. The site selectivity in the [3+2] cycloaddition reaction of ambident 1,3-dipoles was predictably regulated by both the electronic and steric effects of dipolarophiles.Keywords
This publication has 27 references indexed in Scilit:
- A N-heterocyclic carbene derived highly regioselective ambident C–C–S and C–C–N 1,3-dipolar systemChemical Communications, 2006
- Exploring the Border between Concerted and Two‐Step Pathways of 1,3‐Dipolar Cycloadditions of Organic Azides to Cyclic Ketene N,X‐Acetals. – Synthesis and 15N‐NMR Spectra of Zwitterions and Spirocyclic CycloadductsHelvetica Chimica Acta, 2005
- Reverse Regioselection in the Synthesis of Spiropyrazolobarbiturates Using C-Br and C-H NitriliminesSynlett, 2004
- 1,3‐Dithiolanes from Cycloadditions of Alicyclic and Aliphatic Thiocarbonyl Ylides with Thiones: RegioselectivityChemistry – A European Journal, 2003
- A Stepwise Huisgen Cycloaddition Process: Copper(I)-Catalyzed Regioselective “Ligation” of Azides and Terminal AlkynesAngewandte Chemie International Edition, 2002
- Synthesis and structures of 1,3,1′,3′-tetrabenzyl-2,2′-biimidazolidinylidenes (electron-rich alkenes), their aminal intermediates and their degradation productsJournal of the Chemical Society, Perkin Transactions 1, 1998
- Umsetzungen von Bis-[1.3-diaryl-imidazolidinylidenen-(2)] mit Iso-, Isothio- bzw. IsoselenocyanatenEuropean Journal of Organic Chemistry, 1971
- Chemie nucleophiler Carbene, XX HX‐Abspaltung aus 1.3‐Diphenyl‐imidazoliumsalzen. Quecksilbersalz‐Carben‐KomplexeEuropean Journal of Inorganic Chemistry, 1970
- 1,3,6,9-Tetraaza-spiro[4.4]nonane aus Bi-[1,3-diphenyl-imidazolidinyliden-(2)] und lsocyanaten bzw. IsothiocyanatenSynthesis, 1970
- Chemistry of PeraminoethylenesJournal of the American Chemical Society, 1965