Trapping σ-Alkyl-Palladium(II) Intermediates with Arynes Encompassing Intramolecular C−H Activation: Spirobiaryls through Pd-Catalyzed Cascade Reactions

• Published in: Angewandte Chemie International Edition Vol. 55; no. 46; pp. 14389 - 14393
• Main Authors: Pérez-Gómez, Marta, García-López, José-Antonio
• Format: Journal Article
• Language: English
• Published: WEINHEIM Blackwell Publishing Ltd 07.11.2016; Wiley
• Subjects: aryne; carbopalladation; cascade reactions; Chemistry; Chemistry, Multidisciplinary; C−H activation; Physical Sciences; Science & Technology; spirocycles; spirocycles; EFFICIENT SYNTHESIS; carbopalladation; ANION CAPTURE PROCESSES; HYDRIDE ION CAPTURE; cascade reactions; QUEUING CASCADES; C(SP)-H BOND ACTIVATION; aryne; C-H activation; PRODUCT TOTAL-SYNTHESIS; CARBON-CARBON; HECK REACTION; ALKYL-PALLADIUM; CYCLIZATION; C−H activation
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201607976

A palladium‐catalyzed cascade reaction based on the trapping of transient alkyl–PdII intermediates with arynes encompassing a C−H activation step has been developed. This synthetic pathway gives rise to hetero‐spirocyclic scaffolds containing a biaryl motif, and opens up new synthetic strategies in the design of cascade reactions since it gathers several aspects of Pd chemistry, i.e., intra‐ and intermolecular carbopalladation of unsaturated species, C−H activation and C−C coupling processes. From simple to complex: A palladium‐catalyzed cascade Heck carbopalladation/C−H activation/aryne insertion provides easy access to spirobiaryls. The process takes advantage of several aspects of Pd chemistry, i.e., intra‐ and intermolecular carbopalladation of unsaturated species, C−H activation, and C−C coupling processes.