Rhodium‐Catalyzed Annulations of 1,3‐Dienes and Salicylaldehydes/2‐Hydroxybenzyl Alcohols Promoted by 2‐Ethylacrolein
作者:Hong‐Shuang Li、Yang Xiong、Guozhu Zhang
DOI:10.1002/adsc.201800796
日期:2018.11.5
2‐ethylacrolein‐promoted protocol enables the annulation reactions of 1,3‐dienes with either salicylaldehydes or 2‐hydroxybenzyl alcohols leading to 2‐alkylchroman‐4‐ones with high regioselectivity. This research highlights the use of 2‐ethylacrolein which probably serves as a tool of bidentate coordination to rhodium intermediates. Mechanistic studies reveal that the transformation proceeds through the 1,4‐hydroacylation
铑催化的2-乙基丙烯醛促进方案可以实现1,3-二烯与水杨醛或2-羟基苄醇的环化反应,从而产生具有高区域选择性的2-烷基苯并吡喃-4-酮。这项研究强调了2-乙基丙烯醛的使用,它可能用作铑中间体的二齿配位的工具。机理研究表明,转化过程是通过1,4-加氢酰化途径进行的,并通过随后的oxo-Michael加成反应获得不饱和线性酮。