Organocatalytic Domino Michael-Aldol Reaction of Ketones and α,β-Unsaturated Trifluoromethyl Ketones
作者:Jin-Tao Liu、Xiao-Jin Wang、Yan Zhao
DOI:10.1055/s-0028-1083255
日期:2008.12
Pyrrolidine-catalyzed domino Michael-aldol reactionof α,β-unsaturated trifluoromethylketones andketones was achieved under mild conditions; β-hydroxy-β-trifluoromethylcyclohexanones were obtained in high yields with good diastereoselectivities.
Controllable Skeletal and Peripheral Editing of Pyrroles with Vinylcarbenes
作者:Yong Yang、Qingmin Song、Paramasivam Sivaguru、Zhaohong Liu、Dan Shi、Tian Tian、Graham de Ruiter、Xihe Bi
DOI:10.1002/anie.202401359
日期:2024.6.10
The skeletal editing of azaarenes through insertion, deletion, or swapping of single atoms has recently gained considerable momentum in chemical synthesis. Here, we describe a practical skeletal editing strategy using vinylcarbenes in‐situ generated from trifluoromethyl vinyl N‐triftosylhydrazones, leading to the first dearomative skeletal editing of pyrroles through carbon‐atom insertion. Furthermore, depending on the used catalyst and substrate, three types of peripheral editing reactions of pyrroles are also disclosed: α‐ or γ‐selective C–H insertion, and [3+2] cycloaddition. These controllable molecular editing reactions provide a powerful platform for accessing medicinally relevant CF3‐containing N‐heterocyclic frameworks, such as 2,5‐dihydropyridines, piperidines, azabicyclo[3.3.0]octadienes, and allylated pyrroles from readily available pyrroles. Mechanistic insights from experiments and density functional theory (DFT) calculations shed light on the origin of substrate‐ or catalyst‐controlled chemo‐ and regioselectivity as well as the reaction mechanism.