State Key Laboratory of Organometallic Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Road, Shanghai, 200032, China.
J Am Chem Soc. 2021 Aug 18;143(32):12755-12765. doi: 10.1021/jacs.1c05690. Epub 2021 Aug 5.
Catalytic generation of ambiphilic π-allyl-metal complexes and their utility in enantioselective transformations constitutes a powerful approach for introduction of allyl groups to a molecule. Herein an unprecedented cobalt-catalyzed highly site-, diastereo-, and enantioselective protocol for stereoselective formation of nucleophilic allyl-Co(II) complexes followed by addition to aldehydes is presented. The reaction features diastereo- and enantioconvergent conversion of easily accessible allylic alcohol derivatives to diversified enantioenriched homoallylic alcohols with a remarkably broad scope of allyl groups that can be introduced. Mechanistic studies indicated that allyl radical intermediates were involved in this process. These new discoveries establish a new strategy for development of enantioselective transformations through capture of radicals by chiral Co complexes, pushing forward the frontier of Co complexes for enantioselective catalysis.
手性π-烯丙基金属配合物的催化生成及其在对映选择性转化中的应用，为在分子中引入烯丙基基团提供了一种强有力的方法。本文首次报道了钴催化的高区域选择性、非对映选择性和对映选择性的亲核烯丙基-Co(II)配合物的立体选择性形成，随后与醛加成。该反应具有对映体和非对映体转化的特点，可从易得的烯丙醇衍生物转化为多种对映体富集的同烯丙基醇，具有广泛的烯丙基取代基范围。机理研究表明，该过程涉及烯丙基自由基中间体。这些新发现通过手性 Co 配合物捕获自由基为发展对映选择性转化建立了一种新策略，推动了 Co 配合物在手性催化中的前沿发展。
