Synthesis of new (R)-secondary carbinols with different structures via enzymatic resolution
摘要:
The present study deals with the biocatalytic enantioselective synthesis of 19 new chiral alcohols with alkyl (C-11-C-19) and phenyl, substituted phenyl, heteroaromatic, and naphthyl groups 4a-4z with an (R)-configuration and high enantiomeric excess (similar to 100%). The corresponding ketones 1a-1z were synthesized and then reduced with NaBH4 to their racemic alcohols 2a-2z, which were converted into their racemic acetyl derivatives 3a-3z. Enzymes of four different types were used for the enantioselective hydrolysis of these acetyl compounds 3a-3z. The optimal reaction conditions for these four enzymes were established by investigating the enantiomeric excesses by chiral HPLC. Amano lipase from Burkholderica cepacia (Pseudomonas cepacia) AL-PS was determined as the best enzyme in this work This study presents an environmentally friendly and green chemistry method for the synthesis of these new (R)-chiral carbinols 4a-4z. (C) 2011 Elsevier Ltd. All rights reserved.
Asymmetric synthesis of new chiral long chain alcohols
作者:Tülay Yıldız、Ayşe Yusufoğlu
DOI:10.1016/j.tetasy.2010.12.010
日期:2010.12
Sixteen new chiral alcohols with alkyl (C-11-C-19) and aryl, substituted aryl, hetero aryl and biaryl groups 2a-2t were synthesized by three different asymmetric reduction methods from their corresponding ketones 1a-1t. Chiral NaBH4 (method A), chiral BH3 (method B) and chiral AIP (method C) were used as asymmetric reduction catalysts. Chiral NaBH4 was modified by four different ligands 3a-3d, chiral BH3 and chiral AIP by four different ligands 4a-4d. Ligand 4c was synthesized for the first time in this work. Chiral NaBH4 generated chiral alcohols of (R)-configuration and chiral BH3 and chiral AIP of (S)-configuration with high enantiomeric excesses, were analysed by chiral HPLC. In order to determine the ee values by chiral HPLC, sixteen corresponding racemic alcohols, synthesized by reducing their corresponding ketones via NaBH4, were used for chiral resolution on a Daicel OD HPLC column. The sixteen starting ketones were synthesized in this study by Friedel-Craft acylation. The new chiral alcohols were characterized by IR, NMR, (H-1 and C-13), MS, elemental analyses and specific rotation. The reduction methods A, B and C were applied to these ketones for the first time in this study and were compared with each other. The relationship between the structure of the ketone and the yield and the enantiomeric excess was discussed. (C) 2010 Elsevier Ltd. All rights reserved.
Bouda, H.; Borredon, M. E.; Delmas, M., Synthetic Communications, 1987, vol. 17, # 5, p. 503 - 514
作者:Bouda, H.、Borredon, M. E.、Delmas, M.、Gaset A.
DOI:——
日期:——
FAYED, S.;DELMAS, M.;GASET, A., SYNTH. COMMUN., 1982, 12, N 14, 1121-1126
作者:FAYED, S.、DELMAS, M.、GASET, A.
DOI:——
日期:——
BOUDA H.; BORREDON M. E.; DELMAS M.; GASET A., SYNTH. COMMUN., 17,(1987) N 5, 503-513
作者:BOUDA H.、 BORREDON M. E.、 DELMAS M.、 GASET A.
DOI:——
日期:——
Fayed, S.; Delmas, M.; Gaset, A., Synthetic Communications, 1982, vol. 12, # 14, p. 1121 - 1126