当前位置: X-MOL 学术Synthesis › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Asymmetric Kulinkovich Hydroxycyclopropanation of Alkenes Mediated by Titanium(IV) TADDOLate Complexes
Synthesis ( IF 2.2 ) Pub Date : 2019-02-05 , DOI: 10.1055/s-0037-1611709
Marharyta Iskryk 1, 2 , Maryia Barysevich 1, 2 , Maksim Ošeka 1 , Jasper Adamson 3 , Dzmitry Kananovich 1
Affiliation  

Dedicated to Prof. Oleg Kulinkovich on the occasion of his 70th birthday

Abstract

Asymmetric Kulinkovich cyclopropanation of carboxylic ­esters with prochiral alkenes is reported. The process is mediated by ­titanium(IV) (4R,5R)-TADDOLate complexes and affords correspondingly (Z)- or (E)-cyclopropanols with up to 84–87% ee in the event of intra- or intermolecular olefin ligand exchange in intermediate titanacyclopropane [titanium(II)-alkene] species. Configuration of the olefin double bond is preserved in the cyclopropane products, pointing out on ­total retention of configuration at Ti–C bond in the cyclopropane forming step. The results have been interpreted in the framework of ate complex mechanism, suggesting formation of pentacoordinated titanium ate species as a prerequisite of high enantiocontrol.

Asymmetric Kulinkovich cyclopropanation of carboxylic ­esters with prochiral alkenes is reported. The process is mediated by ­titanium(IV) (4R,5R)-TADDOLate complexes and affords correspondingly (Z)- or (E)-cyclopropanols with up to 84–87% ee in the event of intra- or intermolecular olefin ligand exchange in intermediate titanacyclopropane [titanium(II)-alkene] species. Configuration of the olefin double bond is preserved in the cyclopropane products, pointing out on ­total retention of configuration at Ti–C bond in the cyclopropane forming step. The results have been interpreted in the framework of ate complex mechanism, suggesting formation of pentacoordinated titanium ate species as a prerequisite of high enantiocontrol.



中文翻译:

TADDOLate钛(IV)配合物介导的烯烃的不对称Kulinkovich羟基丙烷化反应

专用于奥列格Kulinkovich教授在他的70之际生日

抽象的

据报道羧酸酯与前手性烯烃不对称的库林科维奇环丙烷化。该过程由钛(IV)(4 R,5 R)-TADDOLate络合物介导,如果存在分子内或分子间烯烃配体,则可提供相应的(Z)-或(E)-环丙醇,ee最高可达84-87%中间的钛环丙烷[钛(II)-烯烃]中进行交换。烯烃双键的构型保留在环丙烷产品中,指出在环丙烷形成步骤中Ti-C键的构型完全保留。该结果已在食盐复杂机制的框架内得到解释,表明形成五配位钛酸盐物种是高度对映体控制的先决条件。

据报道羧酸酯与前手性烯烃不对称的库林科维奇环丙烷化。该过程由钛(IV)(4 R,5 R)-TADDOLate络合物介导,如果存在分子内或分子间烯烃配体,则可提供相应的(Z)-或(E)-环丙醇,ee最高可达84-87%中间的钛环丙烷[钛(II)-烯烃]中进行交换。烯烃双键的构型保留在环丙烷产品中,指出在环丙烷形成步骤中Ti-C键的构型完全保留。该结果已在食盐复杂机制的框架内得到解释,表明形成五配位钛酸盐物种是高度对映体控制的先决条件。

更新日期:2019-02-05
down
wechat
bug