Ready Access to Benzannulated [5,5]-Oxaspirolactones Using Au(III)-Catalyzed Cascade Cyclizations
作者:Yash Mankad、Sagar S. Thorat、Pronay Das、Gamidi Rama Krishna、Ravindar Kontham、D. Srinivasa Reddy
DOI:10.1021/acs.joc.1c02843
日期:2022.3.4
showcases an unprecedented Au(III)-catalyzed cascade cyclization of 2-(4-hydroxyalkynyl)benzoates to access benzannulated [5,5]-oxaspirolactones related to biologically active natural products. This reaction proceeds through an initial 5-endo-dig mode of hydroalkoxylation of the alkynol segment to give the oxocarbenium species (via cyclic enol-ether) followed by the addition of carboxylate onto the oxocarbenium
这项工作展示了史无前例的 Au(III) 催化的 2-(4-羟基炔基)苯甲酸酯的级联环化,以获得与生物活性天然产物相关的苯环 [5,5]-氧杂螺内酯。该反应通过炔醇链段的氢化烷氧基化的初始 5 - endo -dig 模式进行,以产生氧代碳鎓物质(通过环烯醇-醚),然后将羧酸盐添加到氧代碳鎓上,从而递送氧螺内酯支架。在测试该方法的范围时,我们发现羟基的空间位阻和电子环境可以改变通过羧酸盐对束缚炔烃的竞争性 6- endo -dig 攻击模式传递异色烯酮的反应途径。