Title:Catalytic and Efficient Synthesis of Optically Active Terminal Epoxides and 1,2-Diols using a New Lanthanum Triflate Assisted C1-Symmetric Bimetallic Chiral Salen Cobalt Complex
VOLUME: 15 ISSUE: 11
Author(s):Deepak Patel, Santosh Singh Thakur*, Sandip S. Shinde and Pradeep Kumar
Affiliation:Department of Chemistry, Guru Ghasidas Vishwavidyalaya, Bilaspur, Chhattisgarh, Department of Chemistry, Guru Ghasidas Vishwavidyalaya, Bilaspur, Chhattisgarh, Organic Chemistry Division, National Chemical Laboratory, Pune, Organic Chemistry Division, National Chemical Laboratory, Pune
Keywords:Chiral epoxides, asymmetric catalysis, bimetallic chiral salen complex, hydrolytic kinetic resolution, lewis acid,
VCD.
Abstract:The catalytic asymmetric synthesis of terminal epoxides and 1,2-diols via a hydrolytic kinetic
resolution of racemic terminal epoxides using a new bimetallic chiral salen CoIII complex incorporated
with La(OTf)3 as a catalyst is reported. The new bimetallic chiral salen CoIII complex bearing
La(OTf)3 was prepared in a one-pot procedure by activation and bimetallic complex formation from
the inactive Jacobsen chiral salen CoII complex (salen = N, N′-bis(3,5-di-tert-butylsalicylidene)-1,2-
cyclohexane-diamine). We observed that C1-symmetric chiral bimetallic Co-complex coordinated with
La(OTf)3 works as a chiral catalyst and remarkably increased the reactivity and enantioselectivity in
the hydrolytic kinetic resolution of terminal epoxides compared to its monometallic analogues.
La(OTf)3 plays a crucial role as an achiral Lewis acid in this process, which is supported by the experimental
observation presented. To explore the absolute configuration of glycidyl butyrate a vibrational
circular dichroism (VCD) spectra was calculated using density functional theory.
