Cobalt-Catalyzed Annulation of Salicylaldehydes and Alkynes to Form Chromones and 4-Chromanones
作者:Junfeng Yang、Naohiko Yoshikai
DOI:10.1002/anie.201510999
日期:2016.2.18
A unique cobalt(I)–diphosphine catalytic system has been identified for the coupling of salicylaldehyde (SA) and an internal alkyne affording a dehydrogenative annulation product (chromone) or a reductive annulation product (4‐chromanone) depending on the alkyne substituents. Distinct from related rhodium(I)‐ and rhodium(III)‐catalyzed reactions of SA and alkynes, these annulation reactions feature
已确定了独特的钴(I)-二膦催化体系,用于水杨醛(SA)和内部炔烃的偶联,取决于炔烃取代基,该炔烃提供脱氢环化产物(色酮)或还原性环化产物(4-苯并二氢醌)。与相关的SA和炔烃的铑(I)和铑(III)催化反应不同,这些环化反应的特征是醛CH氧化SA的氧化反应以及随后SA分子的C = O键的加氢金属化是常见的关键步骤。还原成4-发色环的环也涉及锌作为化学计量还原剂的作用。除了这些机制特征外,本文所述的Co I催化是Rh I-和Rh III的补充SA和内部炔烃的催化反应,特别是在色酮合成的情况下。