ChemInform Abstract: Asymmetric Acylation of sec‐Alcohols with Twisted Amides Possessing Axial Chirality Induced by the Adjacent Asymmetric Center.

Abstract

2000 esterification, ester hydrolysis esterification, ester hydrolysis O 0310 -062Asymmetric Acylation of sec-Alcohols with Twisted Amides Possessing Axial Chirality Induced by the Adjacent Asymmetric Center.-Kinetic resolution of various racemic sec-alcohols and desymmetrization of meso-diols can be performed by using axially chiral twisted amides under neutral conditions. The stereoselectivity is dependent on starting alcohol and the bulkiness of both the acyl group and the C-4 substituent of the chiral auxiliary. Interestingly, with the imidazole substituted amide (IIf), reversed stereoselectivity is observed. -(YAMADA, SHINJI; KATSUMATA, HIROKO; J. Org. Chem. 64 (1999) 26, 9365-9373; Dep. Chem., Fac. Sci., Ochanomizu Univ., Bunkyo, Tokyo 112, Japan; EN)

Acylative Dynamic Kinetic Resolution of Secondary Alcohols: Tandem Catalysis by HyperBTM and Bäckvall’s Ruthenium Complex

“…The 1 H NMR spectrum was identical to that from the literature. 37 [α] D 20 +62.7 (c 1.1, CHCl 3 ); HPLC/csp assay (96:4 er): Daicel CHIRALPAK IC, 25 cm × 4.6 mm i.d., mobile phase 15% MTBE/ 85% heptane, flow rate 1 mL/min, detector UV 210 nm, t R = 5.8 min, major; 6.9 min, minor. The absolute stereochemistry was confirmed by comparison of optical rotation data with that from the literature.…”

“…The 1 H NMR spectrum was identical to that from the literature. 37 [α] D 20 −2.7 (c 0.9, CH 2 Cl 2 ); HPLC/csp assay (56:44 er): Daicel CHIRALPAK IG, 25 cm × 4.6 mm i.d., mobile phase 5% IPA/95% heptane, flow rate 1 mL/min, detector UV 210 nm, t R = 4.5 min, minor; 5.3 min, major.…”

Environmentally Benign Chiral Resolution of trans-1,2-Cyclohexanediol by Two-Step Supercritical Fluid Extraction

“…Previous enantioseparations of the racemic cyclohexanediol, performed not only for analytical purposes, fail to produce both of the pure enantiomers. − We propose a novel procedure in which both enantiomers are produced in high purity while reuse of the resolving agent is also straightforward.…”