Improved catalytic activity of homochiral dimeric cobalt-salen complex in hydrolytic kinetic resolution of terminal racemic epoxides.
Enantiomerically pure epoxides (99%, ee) and diols (98%, ee) from racemic epichlorohydrin, 1,2-epoxypropane, 1,2-epoxyhexane, 1,2-epoxyoctane, and 1,2-epoxydodecane were obtained in 2-12 h by hydrolytic kinetic resolution (HKR) using the recyclable dimeric homochiral Co(III)-salen complex 1' (0.2 mol %) derived from 5,5-(2',2'-dimethylpropane)-di-[(R,R)-{N-(3-tert-butylsalicylidine)-N'-(3',5'-di-tert-butylsalicylidine)}-1,2-cyclohexanediamine] with cobalt(II) acetate. Unlike its monomeric version, the catalyst could be recycled several times without loss in performance. The use of BF(4) as counter ion in HKR reactions was also investigated.
Kureshy
Rukhsana I
RI
Silicates and Catalysis Discipline, Central Salt and Marine Chemicals Research Institute (CSMCRI), Bhavnagar, India. rkureshy@csmcri.org
Singh
Surendra
S
Khan
Noor-Ul H
NU
Abdi
Sayed H R
SH
Ahmad
Irshad
I
Bhatt
Achyut
A
Jasra
Raksh V
RV
D002384:Catalysis; D003035:Cobalt / Q000737:chemistry*; D019281:Dimerization; D004852:Epoxy Compounds / Q000737:chemistry*; D005029:Ethylenediamines / Q000138:chemical synthesis / Q000737:chemistry*; D006868:Hydrolysis; D007700:Kinetics; D015394:Molecular Structure; D013237:Stereoisomerism; D014867:Water / Q000737:chemistry
D004852:Epoxy Compounds; D005029:Ethylenediamines; D014867:Water; D003035:Cobalt; C011452:disalicylaldehyde ethylenediamine