Site‐Selective Alkenylation of Unactivated C(sp3)−H Bonds Mediated by Compact Sulfate Radical

• Published in: Angewandte Chemie International Edition Vol. 60; no. 7; pp. 3545 - 3550
• Main Authors: Ueda, Mitsuhiro, Kamikawa, Kazuya, Fukuyama, Takahide, Wang, Yi‐Ting, Wu, Yen‐Ku, Ryu, Ilhyong
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 15.02.2021; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Bonding; Chemistry; Chemistry, Multidisciplinary; C−H activation; Ethene; Ethylene; Physical Sciences; radicals; Science & Technology; sterics; Substrates; Sulfates; synthetic methods; tungsten; ACTIVATION; radicals; HYDROGEN-ATOM ABSTRACTION; ACYLATION; ALKYLATION; sterics; SULFONES; ALKYNYLATION; C-H BONDS; FUNCTIONALIZATION; ALKENES; tungsten; H activation; DECATUNGSTATE ANION; C− synthetic methods; C−H activation
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202011992

A broad variety of unactivated acyclic and alicyclic substrates cleanly undergo site‐selective alkenylation of unactivated C(sp3)−H bonds with 1,2‐bis(phenylsulfonyl)ethene in the presence of persulfate. This simple transformation furnishes (E)‐2‐alkylvinylphenylsulfones in up to 88 % yield. In contrast with the previously reported decatungstate protocol, the current method is applicable to alkenylation of sterically hindered C−H bonds. This important advantage significantly broadens the substrate scope, and is attributed to the compact size of the sulfate radical employed in the C−H activation and cleavage. Reported here is a new protocol using persulfate anion for site‐selective C(sp3)−H alkenylation with 1,2‐bis(phenylsulfonyl)ethene. As shown, the alkenylation of (3aR)‐(+)‐sclareolide occurs site‐selectively at C8 in spite of the presence of 18 types of C(sp3)−H bonds in the molecule. The hydrogen‐atom transfer reaction by the sulfate radical follows radical polar effects, akin to the decatungstate anion but with a more controlled steric effect.