Enantioselective synthesis of 2-(2-arylcyclopropyl)glycines: Conformationally restricted homophenylalanine analogs

Demir, Ayhan Sıtkı
Sesenoglu, O
Ulku, D
Arici, C
Starting from simple aromatic aldehydes and acetylfuran, (E)-1-(furan-2-yl)-3-arylprop-2-en-1-ones (2) were synthesized in high yields. Cyclopropanation of the C=C bond with trimethylsulfoxonium iodide (Me3SO+I-) furnished (furan-2-yl)(2-arylcyclopropyl)methanones 3 in 90-97% yields. Selective conversion of cyclopropyl ketones to their (E)- and (Z)-oxime ethers 5 and oxazaborolidine-catalyzed stercoselective reduction of the C-N bond followed by separation of the formed diastereoisomers, furnished (2-arylcyclopropyl)(furan-2-yl)methanamines 6 in optically pure form and high yield. Oxidation of the furan ring of (S,S,S)-, (S,R,R)-, (R,S,S)-, and (R,R,R)-6a afforded the four stereoisomers of alpha-(2-phenylcyclopropyl) glycine (1a).


Enantioselective synthesis of both enantiomers of 2-amino-2-(2-furyl)ethan-1-ol as a flexible building block for the preparation of serine and azasugars
Demir, Ayhan Sıtkı; Sesenoglu, O; Aksoy-Cam, H; Kaya, H; Aydogan, K (Elsevier BV, 2003-05-16)
The selective conversion of 1-(2-furyl)-2-hydroxyethan-1-one and ethyl 2-(2-furyl)-2-oxo acetate into (E)- and (Z)-oximes and oxime ethers followed by oxazaborolidine-catalyzed enantioselective reduction using different amino alcohols furnished both enantiomers of the important chiral building block 2-amino-2-(2-furyl)ethan-1-ol with an ee of up to 96%.
Asymmetric synthesis of novel 1,4-aminoalcohol ligands with norbornene and norbornane backbone: use in the asymmetric diethylzinc addition to benzaldehyde
Tanyeli, Cihangir; ERDEM, Mine; ÇAKIR, Esen; KESKİN, Eda (Elsevier BV, 2007-09-27)
The asymmetric synthesis of cis-1,4-aminoalcohols with norbornene and norbornane backbone was performed starting with (2S, 3R)-(-)-cis-hemiester 1 (98% ee). Chemoselective amination with HMPTA followed by Grignard reactions and subsequent LAH reductions afforded compounds 5a-d. cis-Hemiester 1 was also transformed into chiral ligands 7a-f and 9a-d with the DCC coupling method followed by LAH reduction using acyclic, heterocyclic amines and various aniline derivatives and p-toluenesulfonamide, respectively. ...
Asymmetric synthesis of 1,4-amino alcohol ligands with a norbornene backbone for use in the asymmetric diethylzinc addition to benzaldehyde
Tanyeli, Cihangir (Elsevier BV, 2005-06-06)
The asymmetric synthesis of cis-1,4-amino alcohols with a norbornene backbone was performed starting with (2S,3R)(-)-cis-hemiester 2 (98% ee). Chemoselective amination with NH4OH and HMPTA followed by LAH reduction afforded 5 and 7. respectively. Amido ester 6 was transformed into chiral ligand 9 with Grignard reaction followed by LAH reduction. The chiral ligands 5. 7. and 9 were subjected to asymmetric diethylzinc addition to examine their effectiveness as chiral catalysts. Among these, c chiral ligand 7 ...
Organosilanols as Catalysts in Asymmetric Aryl Transfer Reactions
Özçubukçu, Salih; BOLM, Carsten (American Chemical Society (ACS), 2005-03-01)
Various ferrocene-based organosilanols have been synthesized in four steps starting from achiral ferrocene carboxylic acid. Applying these novel planar-chiral ferrocenes as catalysts in asymmetric phenyl transfer reactions to substituted benzaldehydes afforded products with high enantiomeric excesses. The best result (91% ee) was achieved in the addition to p-chlorobenzaldehyde with organosilanol 2b, which has a tert-butyl substituent on the oxazoline ring and an isopropyl group on the silanol fragment.
Amination/annulation of chlorobutenones with chiral amine compounds: synthesis of 1,2,4-trisubstituted pyrroles
Demir, Ayhan Sıtkı; Igdir, AC; Gunay, NB (Elsevier BV, 2005-10-03)
A series of 1,2,4-trisubstituted pyrroles have been synthesized in 83-96% yields on treatment of chiral primary amines, amino alcohols and esters of alpha-amino acids with different chlorobutenones in benzene-triethylamine. The conversions proceed without racemization.
Citation Formats
A. S. Demir, O. Sesenoglu, D. Ulku, and C. Arici, “Enantioselective synthesis of 2-(2-arylcyclopropyl)glycines: Conformationally restricted homophenylalanine analogs,” HELVETICA CHIMICA ACTA, pp. 106–119, 2004, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/57503.