Macrocyclic Mn(III) salen complexes as recyclable catalyst for oxidative kinetic resolution of secondary alcohols

Diethyl Tartrate Linked Chiral Macrocyclic Manganese(III)–Salen Complex for Enantioselective Epoxidation of Olefins and Oxidative Kinetic Resolution of Racemic Secondary Alcohols

“…For the sake of comparison, we used our previously developed catalysts for the epoxidation reaction [17][18][19]24] (Scheme 2). For the sake of comparison, we used our previously developed catalysts for the epoxidation reaction [17][18][19]24] (Scheme 2).…”

“…Following our previously reported reaction procedure, [24] we used 1-phenylethanol as a representative substrate and obtained 85 % ee for the unreacted alcohol (Table 4, entry 1) with 1 mol % of 3 e. Upon increasing the catalyst loading from 1 to 1.5 mol %, the ee value improved up to 95 % ( Table 4, entry 2), but further increasing the catalyst loading was inconsequential for obtaining a higher ee value (Table 4, entry 3). Following our previously reported reaction procedure, [24] we used 1-phenylethanol as a representative substrate and obtained 85 % ee for the unreacted alcohol (Table 4, entry 1) with 1 mol % of 3 e. Upon increasing the catalyst loading from 1 to 1.5 mol %, the ee value improved up to 95 % ( Table 4, entry 2), but further increasing the catalyst loading was inconsequential for obtaining a higher ee value (Table 4, entry 3).…”

“…Herein, we describe the synthesis of a macrocyclic Mn IIIsalen complex capable of epoxidizing nonfunctionalized olefins by using urea/H 2 O 2 as an oxidant with high enantioselectivity (epoxides with up to 92 % ee), as well as the OKR of racemic alcohols with NBS as an oxidant [24] to give alcohols with up to 97 % ee; both of these reactions involve a salen-Mn V -oxo intermediate in the catalytic cycle. [25,26] …”

Copper-cationic salphen catalysts for the oxidation of cyclohexene by oxygen

“…To solve these challenges, ionic compound was developed as an efficient strategy owing to their intriguing physical and chemical properties [19][20][21][22][23][24]. Modified ionic catalysts have obtained common advantages of facilitating product isolation, reusing of the catalysts and in some cases accelerating the reactions [25,26].…”

Oxidative Kinetic Resolution of Secondary Alcohols with Salen–Mn(III)/NBS/NaClO System

“…Many methods, including the asymmetric hydrogenation of prochiral ketones catalyzed by metal complexes [3][4][5][6], the enzymatic kinetic resolution of racemic secondary alcohols through acylation-deacylation reactions [7][8][9], and nonenzymatic kinetic resolution [10,11], have been developed to obtain enantiomerically pure secondary alcohols. Among the many processes known, the oxidative kinetic resolution (OKR) of racemic secondary alcohols is a particularly attractive and efficient method [12][13][14][15]. Several chiral complexes pre-prepared or generated in situ from the corresponding chiral ligands with Pd [16][17][18][19][20][21][22], Ru [23][24][25], Ir [26][27][28], Co [29], Fe [30], and Mn [31][32][33][34][35][36][37][38][39] ions have been used as catalysts for the OKR of racemic secondary alcohols.…”