The sperm whale myoglobin active site mutants (L29H/H64L and F43H/H64L Mb) have been shown to catalyze the asymmetric oxidation of sulfides and olefins. Thioanisole, ethyl phenyl sulfide, and cis-β-methylstyrene are oxidized by L29H/H64L Mb with more than 95% enantiomeric excess (% ee). On the other hand, the F43H/H64L mutant transforms trans-β-methylstyrene into the trans-epoxide with 96% ee. The
Stereochemisty of oxygenation of organic sulphides with pig liver microsomal FAD-containing mono-oxygenase: comparison with cytochrome P-450PB oxidations
The enantiotopic differentiating ability of piglivermicrosomalFAD-containingmono-oxygenase (EC 1.14.13.8) in the oxygenation of nine unsymmetrical sulphides has been investigated. By this enzymatic oxygenation, the sulphides are converted into the corresponding optically active sulphoxides with varying degrees of enantiomeric excess (96–12%).
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
Stereochemistry of intramolecular homolytic substitution at the sulphur atom of a chiral sulphoxide
作者:Athelstan L. J. Beckwith、Douglas R. Boate
DOI:10.1039/c39860000189
日期:——
The formation of the cyclic sulphoxide (R)-(6) by treatment of the bromoarene (R)-(2) with tributylstannane indicates that intramolecular homolytic substitution at the sulphur centre of the sulphoxide group proceeds with strict inversion of configuration.
Asymmetric Sulfoxidation Catalyzed by a Vanadium-Containing Bromoperoxidase
作者:Malin Andersson、Andrew Willetts、Stig Allenmark
DOI:10.1021/jo9712456
日期:1997.11.1
A vanadium-containing bromoperoxidase (VBrPO) from the alga Corallina officinalis has been shown to catalyze the stereoselective oxidation of some aromatic bicyclic sulfides to the corresponding (S)-sulfoxides in high (up to 91%) ee. Hydrogen peroxide was found to have a large effect on the catalyzed reaction, most likely due to an inhibition of VBrPO. High optical and chemical yields were found to