Iron-Mediated Bromocyclization of Olefinic Amides for the Synthesis of Bromobenzoxazines

Abstract

An iron-mediated bromination/cyclization for the synthesis of bromobenzoxazines from olefinic amides has been successfully developed. In this protocol, the simple iron salt FeBr₃ was employed as a bromination reagent, giving the bromobenzoxazine products in moderate to excellent yields. This methodology features good functional group tolerance, gram-scale synthesis, and green reaction conditions by the use of air as the terminal oxidant. Preliminary mechanistic studies suggest that a free radical pathway is involved.

Key words

benzoxazines - bromination - iron salts - aerobic oxidation - molecular oxygen

Publication History

Received: 07 April 2024

Accepted after revision: 05 June 2024

Accepted Manuscript online:
05 June 2024

Article published online:
25 June 2024

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