Coupling of cyclobutenediones with Fischer carbene complexes: A one-step synthesis of cyclopentenediones and/or 5-alkylidenefuranones via net insertion of the carbene unit into a C-C bond

Zora, Metin
The reaction of Fischer carbene-chromium complexes with 3-cyclobutene-1,2-diones has been investigated. In most cases, the major product of the reaction is the C-C bond insertion product, a 2-alkoxy-4-cyclopentene-1,3-dione, accompanied by a minor amount of the partial deoxygenation product, a 4-cyclopentene-1,3-dione. In some cases, 5-alkylidenefuranones are also formed. A mechanism involving oxidative. addition of the coordinatively unsaturated Fischer carbene complex followed by acyl migration and reductive elimination was proposed to account for cyclopentenedione formation. Furanone formation was thought to arise via demetalation of the acyl migration product, followed by O-acylation. An electronic dependence was noted for cyclopentenedione/alkylidene-furanone ratio, which was evaluated using the Hammett equation.


Addition of trifluoromethyltrimethylsilane to acyl phosphonates: Synthesis of TMS-Protected 1-alkyl-1-trifluoromethyl-1-hydroxyphosphonates and 1-aryldifluoroethenyl phosphates
Demir, Ayhan Sıtkı; Eymur, Serkan (American Chemical Society (ACS), 2007-10-26)
Addition reactions of nucleophilic CF3TMS to acyl phosphonates were investigated. Various acyl phosphonates reacted readily with CF3TMS in the presence of K2CO3 in DMF at rt to give 1-alkyl-2,2,2-trifluoro-1-trimethylsilyloxyethylphosphonate in 70−90% yields. When benzoyl phosphonates were used as starting material, after addition of CF3, the formed alcoholate undergoes phosphonate−phosphate rearrangement to form the acyl anion, followed by elimination of F- to give 1-aryldifluoroethenyl phosphates in 87−97...
Synthesis of a New 2,3-Diaminoconduritol with Conduritol F Structure
Ekmekci, Zeynep; Balcı, Metin (2012-09-01)
A new 2,3-diaminoconduritol derivative with the conduritol F structure was prepared starting from cyclohexa-1,4-diene. Initially, a lactam, prepared by the cycloaddition of chlorosulfonyl isocyanate (CSI) to cyclohexa-1,4-diene, was converted into an amino acid. The conversion of the acid functionality into an isocyanate resulted in the formation of an imidazolidinone derivative, formed by an intramolecular cyclization. In the second part of this work, the known anhydride, 3a,4,7,7a-tetrahydroisobenzofuran-...
Synthesis of fused tetrazolone derivatives
Ozcan, Sevil; Ekmekci, Zeynep; Mujde, Berk; Balcı, Metin (2013-01-01)
New fused tetrazolone derivatives were synthesized using homophthalic and maleic anhydrides. Treatment of anhydrides with trimethylsilyl azide opened the lactone rings and formed the corresponding intermediates, which bore 1,3-dipole and dipolarophile functionalities in ortho positions. The intermediates partially underwent internal 1,3-dipolar cycloaddition to produce fused tetrazolone derivatives. When the carbonyl groups in anhydride were not conjugated with any double bond, then a triazine-fused tetrazo...
Reaction of Metal-Carbene Complexes with Cyclobutenediones: The First General C-C Bond Insertion Reaction for Fischer Carbene Complexes
Zora, Metin (American Chemical Society (ACS), 1993-01-01)
Alkylcarbene-chromium complexes react with cyclobutenediones to give 2-alkoxy-4-cyclopentene-1,3-diones in moderate yield, accompanied by varying amounts of 4-cyclopentene-1,3-dione derivatives which result from reduction of the initial product by the chromium byproduct. The reaction is general for a variety of cyclobutenedione derivatives with alkoxy, alkyl, or aryl substituents. The major products of the reaction between arylcarbene complexes and cyclobutenediones are 5-alkylidenefuranone derivatives. A m...
Reaction of cycloheptatriene derivatives with 1,3-diketones in the presence of Mn(OAc)(3)
Sudemen, Mahir Burak; ZENGİN, MUSTAFA; GENÇ, HAYRİYE; Balcı, Metin (2011-01-01)
The reactions of some 1,3-dicarbonyl compounds with cycloheptatriene derivatives in the presence of Mn(OAc)(3) were examined. Cycloheptatriene forms mainly [2+3] and [6+3] dihydrofuran addition products derived from cycloheptatriene. However, the reaction of acetylacetone with cycloheptatriene substituted with an electron withdrawing group exclusively gave products derived from the norcaradiene structure. The formation mechanism of the products as well as the role of the substituent attached to cycloheptatr...
Citation Formats
M. Zora and J. W. HERNDON, “Coupling of cyclobutenediones with Fischer carbene complexes: A one-step synthesis of cyclopentenediones and/or 5-alkylidenefuranones via net insertion of the carbene unit into a C-C bond,” ORGANOMETALLICS, pp. 4429–4436, 1999, Accessed: 00, 2020. [Online]. Available: