Stereoselective synthesis of gamma-lactone fused cyclopentanoids

Gumus, Aysegul
Tanyeli, Cihangir
The stereoselective synthesis of gamma-lactone fused cyclopentanoids applying chemoenzymatic methods is described. rac-2-Hydroxymethyl-1,4,5,6-tetrachloro-7,7-dimethoxybicyclo[2.2.1]hept-5-ene and rac-2-hydroxymethyl-1,4,5,6,7,7-hexachlorobicyclo[2.2.1]hept-5-ene were successfully resolved by Candida rugosa lipase (CRL), to afford enantiomerically enriched products with an ee of 94 and 97%, respectively. The enantiomerically enriched acetates were then subjected to ruthenium and/or cerium catalyzed oxidation to afford alpha-diketones and subsequent alkaline H2O2 mediated oxidative cleavage reaction of alpha-diketones, followed by CH2N2 esterification, gave enantiomerically enriched gamma-lactone fused cyclopentanoids with known absolute configurations.


Stereoselective Synthesis of 1,2,3-Triazolooxazine and Fused 1,2,3-Triazolo-delta-Lactone Derivatives
Gümüş, Ayşegül; Mert, Kudret; Tanyeli, Cihangir (2014-10-01)
The stereoselective synthesis of 1,2,3-triazolooxazine and fused 1,2,3-triazolo--lactone by applying chemoenzymatic methods is described. trans-2-Azidocyclohexanol was successfully resolved by Novozyme 435 with an ee value of 99%. Installation of the alkyne moiety on the enantiomerically enriched azidoalcohol by O-alkylation, followed by intramolecular azidealkyne [3+2] cycloaddition resulted in the desired 1,2,3-triazolooxazine derivative. Enantiomerically pure azidocyclohexanol was also subjected to the H...
Stereoselective construction of 2-oxindole fused spirocycle precursors /
Karahan, Seda; Tanyeli, Cihangir; Department of Chemistry (2019)
Recent literature on the bioactivity of isatin (indoline-2,3-dione) derivatives triggered organic chemists to make use of the unique potential of isatin in asymmetric organocatalytic synthesis. Due to extensive presence of 2-oxindole skeleton, especially spiro-fused cycles, in many natural products, they drew the special interest in the disciplines of medicinal chemistry and agrochemistry. Due to highly reactive prochiral carbonyl group, isatins are potent precursors for the synthesis of 3,3-disubstituted s...
Stereoselective synthesis of spirocyclic cyclopentapyrans by the Pauson-Khand reaction on camphor tethered enynes
Sezer, Serdar; Gumrukcu, Yasemin; ŞAHİN, Ertan; Tanyeli, Cihangir (2008-12-01)
An intramolecular Pauson-Khand reaction of camphor tethered enynes derived from homoallyl, homomethallyl and homopropargyl alcohols is described. Homoallyl, homomethallyl, and homopropargyl moieties are easily constructed on the camphor carbonyl group with excellent diastereoselectivity due to endo-face selectivity, and with known stereochemistry. Each enantiomerically pure enyne affords the conformationally most stable diastereomeric spirocyclic cyclopenta[c]pyran ring system.
Simple chemoenzymatic access to enantiopure pharmacologically interesting (R)-2-hydroxypropiophenones
Demir, AS; Hamamcı, Haluk; Sesenoglu, O; Aydogan, F; Capanoglu, D; Neslihanoglu, R (2001-07-30)
A chemoenzymatic synthesis of pharmacological interesting (R)-2-hydroxypropiophenones starting from propiophenone derivatives is described. Manganese(III) acetate-mediated acetoxylation followed by fungus-mediated hydrolysis of propiophenone derivatives affords (R)-2-hydroxypropiophenones in high enantiomeric excess.
Stereoselective synthesis of cyclopentanoids and cyclitol derivatives originated from polychlorinated norbornene systems
Gümüş, Ayşegül; Tanyeli, Cihangir; Department of Chemistry (2009)
Optically active polychlorinated norbornene systems are important starting compounds for the synthesis of many complex molecules. The synthetic strategy of this study mainly depends upon the enzymatic resolution of hydroxymethyl-substituted polychlorinated norbornene structures. The enantiomerically enriched acetoxymethyl derivatives were synthesized in high ee values by several lipases. The absolute configuration of tetrachlorinated norbornene system was determined by X-ray analysis. The second part of the...
Citation Formats
A. Gumus and C. Tanyeli, “Stereoselective synthesis of gamma-lactone fused cyclopentanoids,” TETRAHEDRON-ASYMMETRY, pp. 1405–1409, 2012, Accessed: 00, 2020. [Online]. Available: