B(C6F5)3‐Catalyzed Ring Opening and Isomerization of Unactivated Cyclopropanes

• Published in: Angewandte Chemie International Edition Vol. 56; no. 14; pp. 4028 - 4032
• Main Authors: Zhang, Zi‐Yu, Liu, Zhi‐Yun, Guo, Rui‐Ting, Zhao, Yu‐Quan, Li, Xiang, Wang, Xiao‐Chen
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 27.03.2017; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Additives; Alkenes; boron; carbocations; Catalysis; Chemistry; Chemistry, Multidisciplinary; C−C activation; Isomerization; Organic compounds; Physical Sciences; Ring opening; Science & Technology; strained molecules; DONOR-ACCEPTOR CYCLOPROPANES; strained molecules; MECHANISM; isomerization; carbocations; VINYLCYCLOPROPANES; C-BOND ACTIVATION; SUBSTITUTED CYCLOPROPANES; 3+2 ANNULATION; 5+2 CYCLOADDITIONS; C C activation; MULTICOMPONENT SYNTHESIS; AMINOCYCLOPROPANES; DENSITY-FUNCTIONAL THEORY; boron; C−C activation
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201700864

Catalytic amounts of B(C6F5)3 promote the ring opening and subsequent isomerization of a series of unactivated cyclopropanes to afford terminal olefins in good yields when a hydrosilane and 2,6‐dibromopyridine are employed as additives. Opening inert cyclopropanes: B(C6F5)3‐catalyzed ring‐opening and isomerization reactions of aryl‐, alkyl‐, and vinyl‐substituted cyclopropanes are described. These reactions generate terminal olefins after a sequential process of C−C bond cleavage, 1,2‐hydride migration, and B(C6F5)3 dissociation. The addition of 2,6‐dibromopyridine and Ph3SiH is crucial for the reactivity.