Diastereoselective Cyclization of 1, 5‐Dienes with the C−H Bond of Pyridine Catalyzed by a Cationic Mono(phosphinoamide) Alkyl Scandium Complex. Issue 1 (8th November 2017)

• Record Type: Journal Article
• Authors: Chen, Yanhui; Song, Di; Li, Jing; Hu, Xiaoyan; Bi, Xianjia; Jiang, Tao; Hou, Zhaomin
• Is Part Of: ChemCatChem. Volume 10:Issue 1(2018)
• Page Start: 159
• Page End: 164
• Publication Date: 2017-11-08
• Subjects: C−H activation -- cyclization -- diastereoselectivity -- dienes -- rare earths; Catalysis -- Periodicals; 541.39505
• DOI: 10.1002/cctc.201700980
• Languages: English
• ISSNs: 1867-3880

Abstract

Abstract: The carbocyclization of non‐conjugated dienes mediated by organometallics is an important reaction for the synthesis of a variety of carbocyclic derivatives, but the direct annulation of dienes with an inert C−H bond of a substrate has remained unexplored to date. We herein report a series of novel rare‐earth dialkyl complexes bearing a phosphinoamide anion and demonstrate that the combination of a mono(phosphinoamido)‐ligated scandium dialkyl complex with B(C6 F5 )3 results in an excellent catalyst for the cis ‐selective cyclization of 1, 5‐dienes with the ortho ‐C(sp 2 )−H bond of pyridines to afford a new family of pyridyl‐functionalized 1, 3‐disubstituted cyclopentane derivatives containing monocyclic, bicyclic, spirocyclic, and heterocyclic skeletons in moderate to excellent yields with high diastereoselectivities ( cis / trans up to 99:1). Abstract : It rings true : The combination of a novel mono(phosphinoamido)‐ligated scandium complex such as2 a ‐Sc with a boron compound such as B(C6 F5 )3 results in a unique and highly efficient catalyst for the cis ‐selective cyclization of 1, 5‐dienes with the ortho ‐C(sp 2 )−H bond of pyridines. The resulting pyridyl‐functionalized 1, 3‐disubstituted cyclopentane derivatives are obtained in excellent yields with high diastereoselectivities.