Cyclotrimerization of benzobarrelene: Synthesis of new isomeric barrelene architectures

Dastan, A
Fabris, F
De Lucchi, O
Guney, M
Balcı, Metin
The cyclotrimerization reaction of benzobarrelene derivatives was investigated. Dibromobenzobarrelene 10 was converted to the bromostannyl derivative 11, which was used as the substrate of the cyclotrimerization reaction. Thus. reaction of 11, with copper(I) thiophene-2-carboxylate (CuTC) gave a mixture of the isomeric cyclotrimers 5 and 6 and the dimers 12 and 13, in addition to a trace of protodestannylated bromoalkene 14 (Scheme 2).


Bifunctional squaramide catalyzed stereoselective Mannich reaction of alpha-azido ketones with isatin-derived ketimines
KARAHAN, SEDA; Tanyeli, Cihangir (Royal Society of Chemistry (RSC), 2020-01-21)
Asymmetric organocatalytic Mannich reaction of alpha-azido ketones and N-Boc protected isatin-derived ketimines were investigated for the first time. Examination of both 2-adamantyl and 3,5-bis(trifluoromethyl)aniline substituted quinine-based squaramides afforded chiral Mannich bases with two contiguous stereogenic centers in high yields (up to 97%) and stereoselectivity (up to dr = 24 : 1 syn : anti and 96% ee). Azido and masked amino functionalities of the potent heterocycle precursor adducts were utiliz...
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...
Chemistry of the benzotropone endoperoxides and their conversion into tropolone derivatives: Unusual endoperoxide rearrangements
Guney, M; Dastan, A; Balcı, Metin (Wiley, 2005-01-01)
The chemistry of two bicyclic endoperoxides, obtained by photooxygenation of 2,3-benzotropone (= 5H-benzocyclohepten-5-one 5) and of its ethyl carboxylate derivative 15, was investigated with the aim of synthesizing the respective benzotropolone derivatives. The reaction of the endoperoxide 10 derived from 5 with thiourea gave the desired benzotropolone, i.e., 6-hvdroxy-5H-benzocyclohepten-5-one (11), in high yield (Scheme 1). On the other hand, the endoperoxide 16 derived from the ethyl carboxylate derivat...
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...
Chemoenzymatic route to various spirocyclic compounds based on enantiomerically enriched tertiary allylic, homoallylic, and homopropargylic alcohols
Tanyeli, Cihangir (Elsevier BV, 2014-04-30)
A ring closing metathesis (RCM) reaction of dienes and an intramolecular Pauson-Khand (PKR) reaction of enynes derived from tertiary allyl, homoallyl, and homopropargyl alcohol backbones to afford the corresponding spirocyclic dihydrofuran and dihydropyrans and spirocyclic cyclopentenone pyrans, respectively, are described. Cyclopent-2-ene anchored tertiary allyl, homoallyl, and homopropargyl alcohols la-c have been efficiently resolved via enzymatic resolution with high ee (up to 90%) with 44%, 40%, and 43...
Citation Formats
A. Dastan, F. Fabris, O. De Lucchi, M. Guney, and M. Balcı, “Cyclotrimerization of benzobarrelene: Synthesis of new isomeric barrelene architectures,” HELVETICA CHIMICA ACTA, pp. 3411–3416, 2003, Accessed: 00, 2020. [Online]. Available: