Palladium-catalyzed ortho-olefination of 2-arylpyrrolidines: A tool for increasing structural complexity in nitrogen heterocycles

TETRAHEDRON

卷:74

Article

Legarda, Pablo D.¹  Garcia-Rubia, Alfonso²  Gomez Arrayas, Ramon^1,3  Carretero, Juan C.^1,3 

[1] Univ Autonoma Madrid, Fac Ciencias, Dept Quim Organ, E-28049 Madrid, Spain

[2] CSIC, Ctr Invest Biol, Ramiro de Maeztu 9, Madrid 28040, Spain

[3] UAM, Inst Adv Res Chem Sci IAdChem, Madrid, Spain

关键词: Pyrrolidine;    Palladium;    C-H alkenylation;    Pyridine directing group;    Benzopyrrolizidine;    Benzazepinone;    Heterocycles;   

DOI  :  10.1016/j.tet.2018.05.076

来源: Elsevier

【 摘 要 】

The dual role of the (2-pyridyl)sulfonyl unit as directing functionality and readily removable N-protecting group has enabled an efficient and practical transformation of 2-arylpyrrolidine derivatives into more complex tricyclic frameworks via palladium-catalyzed ortho-olefination with electron deficient alkenes and subsequent cyclization upon N-deprotection under mild conditions. The key cross coupling step in the presence of N-fluoro-2,4,6-trimethylpyridinium triflate ([F+]) as the terminal oxidant is both highly efficient and tolerant to a variety of steric and electronic changes at both coupling partners. By adequate choice of reductive conditions, the N-sulfonyl deprotection can be directed to the selective formation of benzo-fused pyrrolizidine or fused pyrrolidino-benzazapine frameworks. (C) 2018 Elsevier Ltd. All rights reserved.

【 授权许可】

Free