Chemoenzymatic synthesis of enantiomerically enriched 2-oxobicyclo[m.1.0]alkan-3-yl acetate derivatives

Tanyeli, Cihangir
Racemic alpha'-acetoxy alpha,beta-unsaturated cyclopentanone and cyclohexanone have been resolved into the corresponding enantiomerically enriched alpha'-hydroxylated and acetoxylated compounds with 96-97% ee via PLE hydrolysis. Stereoselectivity in the palladium(II)-catalyzed reaction between the enantiomerically enriched alpha'-acetoxylated compounds and diazomethane has been investigated. In the alpha'-acetoxylated cyclopentenone, preferential cyclopropanation occurs in the anti-form, whereas alpha'-acetoxylated cyclohexenone affords both syn- and anti-products (syn:anti, 61:36%). The relative configuration of the products was determined by NOE experiments.


Stereoselective synthesis of optically active cyclitol precursors via a chemoenzymatic method
Oguzkaya, Funda; Sahin, Ertan; Tanyeli, Cihangir (Elsevier BV, 2006-11-17)
Racemic alpha'-acetoxy alpha,beta-unsaturated cyclohexanone has been converted to the corresponding enantiomerically enriched alpha'-hydroxylated and acetoxylated compounds with 97% ee via enzymatic resolution with PLE. OSO4-Catalyzed dihydroxylation of enantiomerically enriched alpha'-acetoxylated compound afforded a single diastereomer in 85% chemical yield. The absolute configuration of 2,3,6-triacetoxycylohexanone was determined by X-ray diffraction analysis. Subsequent Luche reduction allowed us to obt...
Chemoenzymatic synthesis of alpha(1)- and alpha-acetoxylated cyclic ketones
Tanyeli, Cihangir; Akhmedov, M (Elsevier BV, 2004-06-07)
alpha,beta-Unsaturated and saturated cyclic ketones were selectively oxidized at the alpha'- and alpha-positions using Mn(OAc)(3) and Pb(OAc)(4), respectively, resulting in high chemical yields. The resultant racemic alpha'- and alpha-acetoxylated substrates were resolved into corresponding enantiomerically enriched alpha'- and alpha-hydroxylated and acetoxylated compounds with 96-98% ee via PLE hydrolysis. The absolute configurations of alpha'-acetoxy-alpha,beta-unsaturated cyclic ketones were determined b...
Chemoenzymatic synthesis of both enantiomers of 3-hydroxy-2,3-dihydro-4H-chromen-4-one
Demir, AS; Aybey, A; Sesenoglu, O; Polat, Faruk (Elsevier BV, 2003-06-06)
4-Oxo-3,4-dihydro-2-chromen-3-yl acetate is synthesized using manganese(III)acetate starting from 2,3-dihydro-4H-chromen-4-one. K2CO3 mediated hydrolysis of 4-oxo-3,4-dihdro-2-chromen-3-yl acetate furnished 3-hydroxy-2,3-dihydro-4H-chromen-4-one in high yield. The enantioselective hydrolysis of (+/-)-4-oxo-3,4-dihydro-2-chromen-3-yI acetate in various organic solvent-phosphate buffer (pH7) systems and enantioselective transesterification of (+/-)-3-hydroxy-2,3-dihydro-4H-chromen-4-one in organic solvents wa...
A bis-Lewis basic 2-aminoDMAP/prolinamide organocatalyst for application to the enantioselective synthesis of Warfarin and derivatives
IŞIK, Murat; Akkoca, H. Ufuk; Akhmedov, I. Mecidoglu; Tanyeli, Cihangir (Elsevier BV, 2016-06-01)
A new chiral sec-amine/amidine-base hybrid catalyst, 2-aminoDMAP/prolinamide, is reported, which is able to catalyze conjugate addition of 4-hydroxycoumarin and various benzylideneacetones, a reaction that directly gives anticoagulant Warfarin and its analogues, with good yields (70-87%) and enantioselectivities (58-72%).
Benzaldehyde lyase-catalyzed enantioselective carboligation of aromatic aldehydes with mono- and dimethoxy acetaldehyde
Demir, Ayhan Sıtkı; Sesenoglu, O; Dunkelmann, P; Muller, M (American Chemical Society (ACS), 2003-06-12)
Benzaldehyde lyase from the Pseudomonas fluorescens catalyzes the reaction of aromatic aldehydes with methoxy and dimethoxy acetaldehyde and furnishes (R)-2-hydroxy-3-methoxy-1-arylpropan-1-one and (R)-2-hydroxy-3,3-dimethoxy-1-arylpropan-1-one in high yields and enantiomeric excess via acyloin linkage. Aromatic aldehydes and benzoins are converted into enamine-carbanion-like intermediates prior to carboligation.
Citation Formats
F. D. ÖZDEMİRHAN, M. ÇELİK, S. ATLI, and C. Tanyeli, “Chemoenzymatic synthesis of enantiomerically enriched 2-oxobicyclo[m.1.0]alkan-3-yl acetate derivatives,” TETRAHEDRON-ASYMMETRY, pp. 287–291, 2006, Accessed: 00, 2020. [Online]. Available: