Stereoconvergent Generation of a Contrasteric syn-Bicyclopropylidene (=syn-Cyclopropylidenecyclopropane) by Stille-Like Coupling

Essiz, Selcuk
Balcı, Metin
De Lucchi, Ottorino
ŞAHİN, Ertan
Fabris, Fabrizio
Stereoisomerically pure endo- and exo-7-halo-7-(trimethylstannyl)benzonorcar-3-enes (=endo- and exo-(1-halo-1a,2,7,7a-tetrahydro-1H-cyclopropa[b]naphthalen-1-yl)trimethylstannane) 4 and 6 were selectively obtained by lithiumtin or magnesiumtin transmetalation in good yields (Scheme2 and 3). The reaction of these compounds with copper(I) thiophene-2-carboxylate (CuTC) produced in both cases the corresponding CS-symmetric bicyclopropylidene (=cyclopropylidenecyclopropane) syn-1, a single diastereoisomer (Schemes5 and 6). The structure of syn-1 was undoubtedly elucidated by X-ray single crystal diffraction. The coupling mechanism of the carbenoid cyclopropane is discussed (Scheme7).


Intermolecular one-pot cyclization of formyl-pyrroles of amino acid esters with norephedrine: stereoselective routes to new tricyclic pyrrole-pyrazine-oxazole fused structures
Demir, Ayhan Sıtkı; Subasi, N. Tuna; Sahin, Ertan (Elsevier BV, 2006-10-16)
The treatment of esters of amino acids with dimethoxytetrahydrofuran furnished pyrrole derivatives of amino acid esters. The Wilsmeier-Haack formylation followed by the reaction of the formylated pyrroles with norephedrine afforded a selective formation of the tricyclic pyrrole-pyrazine-oxazole fused structures in one step via the formation of an oxazoline structure and intramolecular lactam formation. Pyrrole-pyrazine-oxazole fused structures were achieved in good yields. The cyclization reaction for the f...
Stereoselective synthesis of optically active cyclopenta[c]pyrans and cyclopenta[c]furans by the intramolecular Pauson-Khand reaction
Sezer, Serdar; ŞAHİN, Ertan; Tanyeli, Cihangir (Elsevier BV, 2010-03-16)
An intramolecular Pauson-Khand reaction of enynes derived from homoallyl, homopropargyl, and allyl alcohols is described. 2-Heteroaryl-substituted homoallyl, homopropargyl, and allyl alcohols are easily and efficiently resolved through enzymatic resolution in high ee (91-99%) and with a known stereochemistry. Each enantiomerically enriched enyne derived from homoallyl and homopropargyl alcohols affords the conformationally most stable diastereomeric cyclopenta[c]pyran ring system as the sole product, wherea...
Regioselective Synthesis of the 5,6-Dihydro-4H-furo[2,3-c]pyrrol-4-one Skeleton: A New Class of Compounds
Koza, Gani; Karahan, Emrah; Balcı, Metin (Wiley, 2010-01-01)
We hereby report the first preparation of the 5,6-dihydro-4H-furo[2.3-c]pyrrol-4-one (3) and its derivatives starting from methyl 3-(methoxycarbonyl)furnan-2-acetate (8). The ester functionality connected to the methylene group was regiospecifically converted to the desired monohydrazide 9. Conversion of 9 into the acyl azide In followed by Curtius rearrangement gave the corresponding isocyanate derivative 11 (Scheme 2). Reaction of 11 with different nucleophiles produced urethane and urea derivatives (Sche...
Stereoselective synthesis of optically active cyclitol precursors via chemoenzymatic method and synthesis of a nucleoside precursor
Oğuzkaya, Funda; Tanyeli, Cihangir; Department of Chemistry (2006)
α'-acetoxylation of α,ß-unsaturated cyclic ketones was adjusted via Mn(OAc)3 in regioselective manner. Then, PLE hydrolysis was carried out so as to afford enantiomerically enriched α'-acetoxylated and α'-hydroxylated cyclic compounds. From our knowledge about the literature and previous works dealing with α'-hydroxylated products which are easily racemized, protection was directly adjusted via acetylation so as to prevent this possibility. Resulting enantiomerically enriched products were subjected to Upjo...
Bis(trimethylsilyl)ethyne as a two-electron alkyne ligand in group 6 carbonylmetal(0) complexes: Photochemical syntheses and comprehensive 2 characterization of M(CO)(5)(eta(Me3SiC)-Me-2=CSiMe3) (M = W, Mo, Cr) and trans-Mo(CO)(4)(eta(2)-Me3SiC=CSiMe3)(2)
Grevels, FW; Jacke, J (American Chemical Society (ACS), 2005-09-12)
Continued irradiation of W(CO)(6) in the presence of excess bis(trimethylsilyl)ethyne (btmse) in n-hexane solution yields W(CO)(5)(eta(2)-btmse) as the sole product, with quantum yields of 0.66 and 0.69 at lambda(exc) = 365 and 313 nm, respectively. Cr(CO)(6) behaves analogously, while with MO(CO)(6) the initially generated Mo(CO)(5)(eta(2)-btmse) undergoes further CO substitution to form trans-Mo(CO)(4)(eta(2)-btmse)(2) as the second product. All four compounds were isolated in crystalline form and fully c...
Citation Formats
M. GÜNEY et al., “Stereoconvergent Generation of a Contrasteric syn-Bicyclopropylidene (=syn-Cyclopropylidenecyclopropane) by Stille-Like Coupling,” HELVETICA CHIMICA ACTA, pp. 941–950, 2013, Accessed: 00, 2020. [Online]. Available: