Formal Lossen Rearrangement/[3+2] Annulation Cascade Catalyzed by a Modified Cyclopentadienyl RhIII Complex

• Published in: Chemistry : a European journal Vol. 24; no. 22; pp. 5723 - 5727
• Main Authors: Yamada, Takayuki, Shibata, Yu, Kawauchi, Susumu, Yoshizaki, Soichi, Tanaka, Ken
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 17.04.2018
• Subjects: Alkynes; annulation; Cascade chemical reactions; Chemical reactions; Chemistry; cyclopentadienyl complexes; C−H activation; Hydrogen bonds; Indoles; Lossen rearrangement; Organic chemistry; Pyrroles; rhodium
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201801125

It has been established that a cyclopentadienyl RhIII complex with two phenyl groups and a pendant amide moiety catalyzes the formal Lossen rearrangement/[3+2] annulation cascade of N‐pivaloyl benzamides and acrylamides with alkynes leading to substituted indoles and pyrroles. Mechanistic studies revealed that this cascade reaction proceeds via not the Lossen rearrangement to form anilides or enamides but C−H bond cleavage, alkyne insertion, and the formal Lossen rearrangement. Adding rings: It has been established that a cyclopentadienyl RhIII complex with two phenyl groups and a pendant amide moiety catalyzes the formal Lossen rearrangement/[3+2] annulation cascade of N‐pivaloyl benzamides and acrylamides with alkynes leading to substituted indoles and pyrroles. This cascade reaction does not proceed via the Lossen rearrangement to form anilides or enamides but by C−H bond cleavage, alkyne insertion, and the formal Lossen rearrangement.