Planar Chiral Flavinium Salts - Prospective Catalysts for Enantioselective Sulfoxidation Reactions
作者:Radek Jurok、Radek Cibulka、Hana Dvořáková、František Hampl、Jana Hodačová
DOI:10.1002/ejoc.201000592
日期:2010.9
the reaction catalysed by 5-ethyl-3,10-dimethylisoalloxazinium perchlorate, which indicates that the bulky shielding substituent does not influence the catalytic activity of the flavinium unit. The turnover frequency for the oxidation of thioanisole with hydrogen peroxide with 2b is 870 h -1 . The enantiomerically pure salts (+)-2b and (―)-2b were prepared from the pure enantiomers (+)-3b and (―)-3b of
制备了一种新型平面手性黄酮盐,3-benzyl-5-ethyl-10-(8-phenylnaphthalen-1-yl)isoalloxazinium perchlorate (2b),它带有一个苯基帽,覆盖了isoalloxazinium 骨架平面的一侧。作为硫化物对映选择性 H 2 O 2 氧化的潜在催化剂。在外消旋 2b 存在下硫化物的 H 2 O 2 氧化速率与 5-乙基-3,10-二甲基异恶嗪鎓高氯酸盐催化反应的速率相当,这表明庞大的屏蔽取代基不影响催化活性黄素单位。用过氧化氢和 2b 氧化茴香硫醚的周转频率是 870 h -1 。对映体纯盐 (+)-2b 和 (-)-2b 由 3-苄基-10-(8-苯基萘-1-基)异咯嗪的纯对映体 (+)-3b 和 (-)-3b 制备( 3b) 通过在手性固定相上外消旋 3b 的 HPLC 分离获得。对映体纯盐 (+)-2b 和 (-)-2b 以