Asymmetric Yttrium‐Catalyzed C(sp3)−H Addition of 2‐Methyl Azaarenes to Cyclopropenes

• Published in: Angewandte Chemie International Edition Vol. 56; no. 31; pp. 9207 - 9210
• Main Authors: Luo, Yong, Teng, Huai‐Long, Nishiura, Masayoshi, Hou, Zhaomin
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 24.07.2017
• Edition: International ed. in English
• Subjects: asymmetric catalysis; Chemical synthesis; Cyclopropane; cyclopropenes; Enantiomers; Hydrogen bonds; norbornenes; Organic compounds; Pyridines; Yttrium; yttrium catalysis; norbornenes; cyclopropenes; pyridines; asymmetric catalysis; yttrium catalysis
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201705431

An enantioselective C−H addition to a C=C bond represents the most atom‐efficient route for the construction of chiral carbon–carbon skeletons, a central research topic in organic synthesis. We herein report the enantioselective yttrium‐catalyzed C(sp3)−H bond addition of 2‐methyl azaarenes, such as 2‐methyl pyridines, to various substituted cyclopropenes and norbornenes. This process efficiently afforded a new family of chiral pyridylmethyl‐functionalized cyclopropane and norbornane derivatives in high yields and high enantioselectivities (up to 97 % ee). Enantioselective C(sp3)−H bond additions of 2‐methyl azaarenes, such as 2‐methylpyridines, to substituted cyclopropenes and norbornenes have been achieved by using a chiral half‐sandwich yttrium catalyst. This process afforded a series of chiral pyridylmethyl‐functionalized cyclopropane and norbornane derivatives in good yields, high enantioselectivity, and 100 % atom efficiency.