Electrochemical Synthesis of Dimeric λ³-Bromane: Platform for Hypervalent Bromine(III) Compounds

Abstract

A straightforward and scalable approach to a previously unreported class of cyclic hypervalent Br(III) species capitalizes on the anodic oxidation of aryl bromide to dimeric benzbromoxole that serves as a versatile platform to access a range of structurally diverse Br(III) congeners such as acetoxy-, alkoxy-, and ethynyl-λ 3 -bromanes as well as diaryl-λ 3 -bromanes. The synthetic utility of dimeric λ 3 -bromane is exemplified by photoinduced Minisci-type heteroarylation reactions and benzylic oxidation.

Organohypervalent heterocycles

“…Recently, Sokolovs and Suna developed an excellent example of electrochemical synthesis of a range of diverse cyclic hypervalent bromine( iii ) compounds ( 150 ). 326 The dimeric benzobromoxole ( 149 ), obtained through anodic oxidation of aryl bromide ( 148 ), can be converted to numerous synthetically useful Br( iii ) compounds ( 150 ) (Scheme 35).…”

Hypervalent Halogen Compounds in Electrochemical Reactions: Advantages and Prospects

“…Building on this knowledge, Suna and co-workers expanded this platform for the electrochemical synthesis of dimeric bromine(III) compounds (Scheme 18). [60] The anodically generated benzbromoxole 75 serves as a versatile platform to access diverse bromine(III) congeners, including acetoxy-, alkoxy-, ethynyl-and diaryl bromanes. Compound 75 is a crystalline solid that can be stored in the freezer for 8 weeks.…”

Diaryl hypervalent bromines and chlorines: synthesis, structures and reactivities

“…Remarkably, 29 can be considered as a precursor of a wide range of hypervalent bromines, such as the peculiar diaryl λ 3 -bromane 30 ( Scheme 7 ). 67 …”