84413-74-1Relevant articles and documents
A study of enantioselective syntheses by Sharpless asymmetric oxidation for aryl sulfoxides containing oxygen groups at the ortho position
Takei, Takanori,Takayama, Jun,Xuan, Meiyan,Tomoda, Misa,Miyamae, Hiroshi,Sakamoto, Takeshi
, (2021/03/16)
Abstract: While ortho-alkoxy aryl sulfoxides including various substituents were synthesized by Sharpless asymmetric oxidation reaction, we optimized the reaction conditions and screened better combination of starting materials to obtain high enantioselectivity. The result suggested new information that electron-withdrawing substituents on the aromatic ring have a strong influence upon enantioselectivity of the products. Also, several chiral ligands for Sharpless asymmetric oxidation reaction were evaluated to improve the enantioselectivity. Graphic abstract: High enantioselectivity of ortho-alkoxy aryl chiral sulfoxides have been achieved by Sharpless oxidation reaction using Ti(O-i-Pr)4 and diethyl tartrate under anhydrous condition. In particular, the enantioselctivity of products was influenced by electron-withdrawing substituents on the aromatic ring, such as nitro, ester and aldehyde groups.[Figure not available: see fulltext.]
Two enantiocomplementary Baeyer-Villiger monooxygenases newly identified for asymmetric oxyfunctionalization of thioether
Liu, Yafei,Ni, Ye,Wei, Shiyu,Xu, Guochao,Zhou, Jieyu
, (2021/08/19)
Two enantiocomplementary Baeyer-Villiger monooxygenases RaBVMO and AmBVMO were identified by genome mining for the asymmetric sulfoxidation. Both recombinant BVMOs have optimal pH of 9.0 and temperature of 35 °C. The half-lives of RaBVMO and AmBVMO at 30 °C were 24.4 and 24.6 h. RaBVMO and AmBVMO exhibited broad substrate spectrum and could catalyze the oxidization of various compounds including fatty ketones, cyclic ketones, and thioethers. Kinetic parameters analysis revealed that both RaBVMO and AmBVMO displayed higher catalytic efficiency toward thioanisole than cyclohexanone. As much as 50 mM thioanisole could be completely oxidized by AmBVMO and RaBVMO with 99% (R) and 95% (S), respectively. Molecular docking analysis further provides evidence for the complementary enantioselectivity of RaBVMO and AmBVMO. Our results demonstrate the potential application of the two novel BVMOs in asymmetric synthesis of sulfoxides.
Light-controlled cooperative catalysis of asymmetric sulfoxidation based on azobenzene-bridged chiral salen TiIVcatalysts
Fu, Wenqin,Gao, Mengqiao,Li, Chaoping,Pi, Yibing,Tan, Rong,Wang, Weiying,Yin, Donghong
supporting information, p. 5993 - 5996 (2020/06/04)
Incorporation of azobenzene into the linker of bimetallic chiral salen TiIVcatalysts allowed the photoswitchable arrangement of the two Ti(salen) units throughcis/transphotoisomerization of azobenzene. The differently arranged Ti(salen) units changed their cooperative function to reflect the positional relationships, as a result, their efficiency as cooperative catalysts in asymmetric sulfoxidation could be readily controlled by light stimuli.
