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Updated: Jul 23, 2025

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Published on: April 22, 2016
Visible Light Promoted Brominative Dearomatization of Biaryl Ynones to Spirocycles
Barnali Roy1, Puspendu Kuila1, Debayan Sarkar2
1Department of Chemistry, National Institute of Technology, Rourkela, Odisha 769008, India.
Abstract:
Bromine induced spiro cyclization of biaryl ynones facilitated the synthesis of spiro[5,5]trienones suitable for extended functionality at the C(3') position. Herein, a step-economic photo-oxidative brominative carbannulation of biaryl ynones employing ammonium bromide and riboflavin tetraacetate (RFTA) has been developed. The reactivity between distal phenyl C-H activated ortho-annulation and dearomative ipso-annulation is well exemplified. The eminent features of the methodology include metal-free, external additive free, low-loading photocatalyst (0.1 mol %), and use of a simple precursor.
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