Aminocyclopentadienyl ruthenium complexes as racemization catalysts for dynamic kinetic resolution of secondary alcohols at ambient temperature
SCIE
SCOPUS
- Title
- Aminocyclopentadienyl ruthenium complexes as racemization catalysts for dynamic kinetic resolution of secondary alcohols at ambient temperature
- Authors
- Choi, JH; Choi, YK; Kim, YH; Park, ES; Kim, EJ; Kim, MJ; Park, JW
- Date Issued
- 2004-03-19
- Publisher
- AMER CHEMICAL SOC
- Abstract
- Aminocyclopentadienyl. ruthenium complexes, which can be used as room-temperature racemization catalysts with lipases in the dynamic kinetic resolution (DKR) of secondary alcohols, were synthesized from cyclopenta-2,4-dienimines, Ru-3(CO)(12), and CHCl3: [2,3,4,5-Ph-4(eta(5)-C4CNHR)]Ru-(CO)(2)Cl (4: R = i-Pr; 5: R = n-Pr; 6: R = t-Bu), [2,5-Me-2-3,4-Ph-2(eta(5)-C4CNHR)]Ru(CO)(2)Cl (7: R = i-Pr; 8: R = Ph), and [2,3,4,5-Ph-4(eta(5)-C4CNHAr)]Ru(CO)(2)Cl (9: Ar = p-NO2C6H4; 10: Ar = p-ClC6H4; 11: Ar = Ph; 12: Ar = p-OMeC6H4; 13: Ar = p-NMe2C6H4). The tests in the racemization of (S)-4-phenyl-2-butanol showed that 7 is the most active catalyst, although the difference decreased in the DKR. Complex 4 was used in the DKR of various alcohols; at room temperature, not only simple alcohols but also functionalized ones such as allylic alcohols, alkynyl alcohols, diols, hydroxyl esters, and chlorohydrins were successfully transformed to chiral acetates. In mechanistic studies for the catalytic racemization, ruthenium hydride 14 appeared to be a key species. It was the major organometallic species in the racemization of (S)-1-phenylethanol with 4 and potassium tertbutoxide. In a separate experiment, (S)-1-phenylethanol was racemized catalytically by 14 in the presence of acetophenone.
- Keywords
- HYDROXY ACID-DERIVATIVES; OPPENAUER-TYPE OXIDATION; DIRECTED EVOLUTION; ALLYLIC ALCOHOLS; ORGANIC-SOLVENTS; ASYMMETRIC TRANSFORMATIONS; ENZYME IMMOBILIZATION; IONIC HYDROGENATIONS; ENANTIOSELECTIVE ACYLATION; HYDRIDE TRANSFER
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/18020
- DOI
- 10.1021/JO0355799
- ISSN
- 0022-3263
- Article Type
- Article
- Citation
- JOURNAL OF ORGANIC CHEMISTRY, vol. 69, no. 6, page. 1972 - 1977, 2004-03-19
- Files in This Item:
- There are no files associated with this item.
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.