Au(I) and HOTf‐Catalyzed Cascade [5+1]‐Annulations between Allenylacetals and Diazo Esters To Form 1,3‐ and 2,3‐Disubstituted Naphthoates, Respectively
作者:Satish Bhausaheb Dawange、Rai‐Shung Liu
DOI:10.1002/adsc.202300605
日期:2023.11.21
Gold-catalyzed [5+1]-annulations between allenylacetals with diazo esters to form 1,3-disubstituted naphthoate derivatives are described. Notably, this reaction chemoselectivity is switched to 2,3-naphthoate products when using the HOTf catalyst. Mechanistic studies of these reactions support an acetal activation, in which oxoniums are formed initially, followed by attack of the allene, generating
描述了金催化的联烯基缩醛与重氮酯之间的[5+1]-环化反应,形成1,3-二取代的萘甲酸酯衍生物。值得注意的是,当使用 HOTf 催化剂时,该反应的化学选择性转变为 2,3-萘甲酸酯产物。这些反应的机理研究支持缩醛活化,其中最初形成氧鎓,然后攻击丙二烯,产生烯丙基阳离子以捕获α-重氮酯。在金催化中,此类重氮加成中间体发生 Roskamp 重排,而在 HOTf 催化中,相同的中间体发生 Conia-ene 反应。