Abrams R, Jesani MH, Browning A, Clayden J. Triarylmethanes and their Medium-Ring Analogues by Unactivated Truce-Smiles Rearrangement of Benzanilides.
Angew Chem Int Ed Engl 2021;
60:11272-11277. [PMID:
33830592 PMCID:
PMC8252078 DOI:
10.1002/anie.202102192]
[Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/01/2021] [Indexed: 12/17/2022]
Abstract
Intramolecular nucleophilic aromatic substitution (Truce–Smiles rearrangement) of the anions of 2‐benzyl benzanilides leads to triarylmethanes in an operationally simple manner. The reaction succeeds even without electronic activation of the ring that plays the role of electrophile in the SNAr reaction, being accelerated instead by the preferred conformation imposed by the tertiary amide tether. The amide substituent of the product may be removed or transformed into alternative functional groups. A ring‐expanding variant (n to n+4) of the reaction provided a route to doubly benzo‐fused medium ring lactams of 10 or 11 members. Hammett analysis returned a ρ value consistent with the operation of a partially concerted reaction mechanism.
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