Preparation of enantiomerically pure p-substituted phenylethyl hydroperoxides by kinetic resolution and their use as enantioselective oxidants in the asymmetric Weitz–Scheffer epoxidation of E-chalcone
作者:Kani Zilbeyaz、Hamdullah Kilic、Melda Sisecioglu、Hasan Ozdemir、Azize Alayli Güngör
DOI:10.1016/j.tetasy.2012.04.005
日期:2012.4
para-substituted phenylethyl hydroperoxides by Raphanus sativus L. (black radish peroxidase) in the presence of guaiacol is reported. The peroxidase enzyme recognized (R)-configured alkyl aryl hydroperoxides, which furnished optically active (S)-hydroperoxides and (R)-alcohols. Kinetic resolution of tertiary hydroperoxides by the enzyme was unsuccessful. This study also shows how the optically active p-substituted
的各种继发的动力学拆分对由取代的苯乙基氢过氧化物萝卜报道L.(黑萝卜过氧化物酶)在愈创木酚的存在。过氧化物酶识别(R)-构型的烷基芳基氢过氧化物,其提供了光学活性的(S)-氢过氧化物和(R)-醇。该酶不能动力学拆分叔氢过氧化物。这项研究还表明,在存在KF-Al 2的情况下,所获得的旋光性对位取代的(S)-氢过氧化物如何在E-查耳酮的不对称Weitz-Scheffer环氧化中用作对映选择性氧化剂。以O 3为基。在所有情况下,查耳酮环氧化物与(α小号,β - [R ),得到-构型为主要异构体。在最佳反应条件下,在-40°C的CH 3 CN中,查尔酮环氧化物的对映体过量高达49%。