Rhodium-Catalyzed Tandem Cyclization/SiC Activation Reaction for the Synthesis of Siloles

• Published in: Angewandte Chemie International Edition Vol. 53; no. 22; pp. 5667 - 5671
• Main Authors: Zhang, Qing-Wei, An, Kun, He, Wei
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 26.05.2014; WILEY‐VCH Verlag; Wiley
• Subjects: Activation; Activation analysis; Additives; Bonding; Carbon - chemistry; Catalysis; Chemistry; Chemistry, Multidisciplinary; Cyclization; heterocycles; Heterocyclic Compounds - chemistry; luminescence; Photoluminescence; Physical Sciences; Quantum Theory; Rhodium; Rhodium - chemistry; Science & Technology; Silanes - chemical synthesis; Silanes - chemistry; silicon; Silicon - chemistry; Strategy; Synthesis; synthetic methods; Utilities; POLYMERS; ASYMMETRIC-SYNTHESIS; BENZOSILOLE DERIVATIVES; PHOTOPHYSICAL PROPERTIES; ALKYNES; CLEAVAGE; CYCLOADDITION; luminescence; silicon; heterocycles; SILANES; CARBON-SILICON BOND; SILAFLUORENES; synthetic methods; rhodium
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.201400828

Siloles represent an important emerging class of photoluminescent materials. Reported herein is a new synthetic strategy involving a tandem cyclization/SiC activation reaction featuring high efficiency, wide substrate scope, and practical utility. This method enabled the first synthesis of benzofuran siloles as well as rapid access to conjugated siloles. During the course of the study we also uncovered an unusual yet general SiC(sp2) activation in the presence of π acids. Bare your siloles: The title reaction involving SiC(sp3) bond activation was developed for the synthesis of photoluminescent siloles. An external proton source promotes the rhodium catalyst turnover. In addition, the selective activation of SiC(sp2) bonds was discovered through the use of a π‐acid additive. This method enabled the first synthesis of benzofuran siloles and provided rapid access to conjugated siloles by facile derivatization.