已经通过三种途径制备了在C-3处带有活化三烷基甲硅烷基氧基的2-Aza-1,3-二烯。第一条途径涉及N-酰基酰亚胺的甲硅烷基化,其可从亚氨基醚盐酸盐和酰氯容易获得。根据朝向这些双活化二烯的更通用的途径,通过在三乙胺的存在下与酰氯反应,将由不可烯化的醛衍生的N-三烷基甲硅烷基酰亚胺酯和N-三烷基甲硅烷基亚胺方便地以一锅法转化为相应的氮杂二烯。最后,可以通过在三乙胺的存在下用三烷基甲硅烷基三氟甲磺酸酯在两个氧上将戊二酰亚胺直接甲硅烷基化来制备环状二烯。2-氮二烯的构型和构象已由1 H,13确定C和15 N NMR光谱。
readily available from iminoether hydrochlorides and acid chlorides. According to a more general route towards these doubly activated dienes, N-trialkylsilylimidates and N-trialkylsilylimines derived from non-enolizable aldehydes were conveniently converted in a one-pot sequence into the corresponding azadienes by reaction with an acid chloride in the presence of triethylamine. Finally, cyclic dienes could
已经通过三种途径制备了在C-3处带有活化三烷基甲硅烷基氧基的2-Aza-1,3-二烯。第一条途径涉及N-酰基酰亚胺的甲硅烷基化,其可从亚氨基醚盐酸盐和酰氯容易获得。根据朝向这些双活化二烯的更通用的途径,通过在三乙胺的存在下与酰氯反应,将由不可烯化的醛衍生的N-三烷基甲硅烷基酰亚胺酯和N-三烷基甲硅烷基亚胺方便地以一锅法转化为相应的氮杂二烯。最后,可以通过在三乙胺的存在下用三烷基甲硅烷基三氟甲磺酸酯在两个氧上将戊二酰亚胺直接甲硅烷基化来制备环状二烯。2-氮二烯的构型和构象已由1 H,13确定C和15 N NMR光谱。
(4+3) Annulation of Donor‐Acceptor Cyclopropanes and Azadienes: Highly Stereoselective Synthesis of Azepanones
作者:Stefano Nicolai、Jérôme Waser
DOI:10.1002/anie.202209006
日期:2022.9.5
Azepanones are important and widespread seven-membered heterocycles, but their synthesis is challenging. A convergent method to access these scaffolds was developed relying on a (4+3) annulation reaction of azadienes and donor-acceptor cyclopropanes. Good to excellent yields and high diastereoselectivity were achieved using Yb(OTf)3 as the catalyst. Asymmetric induction was possible with Cu(OTf)2 in