Asymmetric Synthesis of Spirobenzazepinones with Atroposelectivity and Spiro-1,2-Diazepinones by NHC-Catalyzed [3+4] Annulation Reactions
A strategy for the NHC-catalyzed asymmetric synthesis of spirobenzazepinones, spiro-1,2-diazepinones, and spiro-1,2-oxazepinones has been developed via [3+4]-cycloaddition reactions of isatin-derived enals (3C component) with in-situ-generated aza-o-quinone methides, azoalkenes, and nitrosoalkenes (4atom components). The [3+4] annulation strategy leads to the seven-membered target spiro heterocycles bearing an oxindole moiety in high yields and excellent enantioselectivities with a wide variety of substrates. Notably, the benzazepinone synthesis is atroposelective and an all-carbon spiro stereocenter is generated.
CCDC 1453056: Experimental Crystal Structure Determination
Related Article: Lei Wang, Sun Li, Marcus Blümel, Arne R. Philipps, Ai Wang, Rakesh Puttreddy, Kari Rissanen, Dieter Enders|2016|Angew.Chem.,Int.Ed.|55|11110|doi:10.1002/anie.201604819
CCDC 1413502: Experimental Crystal Structure Determination
Related Article: Lei Wang, Sun Li, Marcus Blümel, Arne R. Philipps, Ai Wang, Rakesh Puttreddy, Kari Rissanen, Dieter Enders|2016|Angew.Chem.,Int.Ed.|55|11110|doi:10.1002/anie.201604819