Industrialization Studies of the Jacobsen Hydrolytic Kinetic Resolution of Epichlorohydrin

Modular Approach for the Development of Supported, Monofunctionalized, Salen Catalysts

“…By simply washing the obtained Et 2 O solution with water, ( R )-3-chloro-1,2-propandiol 19 can be removed nearly quantitatively, resulting in pure ( S )- 18 . This protocol is considered to be an important advantage to the normally used methodology of distilling off 18 from the crude reaction mixture, because remaining Co(III)−salen complexes are reported to catalyze the decomposition and the racemization of the epoxide during the purification process. ,, Because the polymeric CoOAc complex p(10a) gave the best selectivities, we chose this catalyst to study the reusability of our polymeric Co−salen catalysts. After reoxidation with O 2 in the presence of acetic acid, recycled p(10c) showed the same resolution rate and selectivity as the original polymeric catalyst p(10c) (Figure , 61.8% conversion, > 99% ee of ( S )- 18 after 150 min).…”

Dinuclear salen cobalt complex incorporating Y(OTf)3: enhanced enantioselectivity in the hydrolytic kinetic resolution of epoxides

“…[1][2][3][4] Catalytic asymmetric ring opening of racemic terminal epoxides with water (hydrolytic kinetic resolution, HKR) using Jacobsen's chiral (salen) Co III -OAc complex as chiral catalyst has been widely applied and is highly efficient for the preparation of enantioenriched epoxides in academic and industrial sectors. 5,6 The catalytically inactive chiral salen Co II complex is activated by aerobic oxidation via one electron transfer reaction to give a chiral salen Co III complex; this is promoted by many Brønsted acids, which was found mechanistically to exhibit a second order dependence on the salen [Co III ] catalyst unit routed through a cooperative bimetallic mechanism. 7,8 The metal valence change from Co III to Co II during the HKR of racemic epoxides has been studied in detail.…”

Poly(styrene) Resin‐Supported Cobalt(III) Salen Cyclic Oligomers as Active Heterogeneous HKR Catalysts

“…The fact that the products of the reaction self‐separate under reaction conditions can be a very attractive feature to the industrial preperation of enantiopure epoxides as the energy intensive azeotropic distillation procedures and the use of solvents for extraction to separate components from the reaction mixure can be omitted 4. We suggest that diffusion is the main reason behind this rate enhancement.…”

“…The hydrolytic kinetic resolution (HKR) of terminal epoxides using a cobalt(III) salen catalyst is one of these epoxide‐opening reaction 3. It serves on an industrial scale to prepare chiral epoxides and diols 4. Cobalt(III) salen complexes have been supported on various materials with the aim of increasing the activity of the salen catalysts and/or to recover the metal species from the reaction mixture 5…”