Bifunctional squaramide catalyzed stereoselective Mannich reaction of alpha-azido ketones with isatin-derived ketimines

Tanyeli, Cihangir
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 utilized in representative examples.


Carboligation reactions with benzaldehyde lyase immobilized on superparamagnetic solid support
Sopaci, S. Betuel; Turan, Ilke Simsek; Tural, Bilsen; Volkan, Mürvet; Demir, Ayhan Sıtkı (Royal Society of Chemistry (RSC), 2009-01-01)
Histidine-tagged recombinant benzaldehyde lyase (BAL, EC was efficiently immobilized to surface-modified magnetic particles with affinity ligand binding. In addition to conventional benzoin condensation reactions, two important representative BAL-catalyzed carboligation reactions, were also performed with this magnetically responsive biocatalyst. The results obtained from the carboligation reactions that were performed with this simple and convenient heterogenous biocatalyst were comparable to tha...
Cyclotrimerization of benzobarrelene: Synthesis of new isomeric barrelene architectures
Dastan, A; Fabris, F; De Lucchi, O; Guney, M; Balcı, Metin (Wiley, 2003-01-01)
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).
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.
Functionalization of oxabenzonorbornadiene: Manganese(III)-mediated oxidative addition of dimedone
ÇALIŞKAN, Raşit; Sari, Ozlem; Balcı, Metin (Wiley, 2017-09-01)
3-Chloro-1,2,3,4-tetrahydro-1,4-epoxynaphthalen-2-yl)-3-hydroxy-5,5-dimethylcy-clohex- 2-en-1-one, synthesized by the reaction of oxabenzonorbornadiene with Mn(OAc)(3) and dimedone in the presence of HCl in acetic acid, was submitted to ring-opening reactions with BBr3 and H2SO4. Reaction with BBr3 yielded 2 products, a 5-membered ring and an 8-membered ring, with the former being the major product. However, the H2SO4-supported reaction exclusively formed an 8-membered ring. The mechanism of formation of th...
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...
Citation Formats
S. KARAHAN and C. Tanyeli, “Bifunctional squaramide catalyzed stereoselective Mannich reaction of alpha-azido ketones with isatin-derived ketimines,” ORGANIC & BIOMOLECULAR CHEMISTRY, pp. 479–487, 2020, Accessed: 00, 2020. [Online]. Available: