Synthesis of Vinyl Bromides Via Reaction of Vinyl Boronic Acids with Sodium Bromide

Abstract

Vinyl halides have proven to be useful synthetic intermediates.^1,2 Recently, it was discovered that vinyl iodides are more stable to in-vivo deiodination than the corresponding alkyl iodides.^3,4 This fact makes the vinyl halides potentially valuable in the design and syntheses of radiopharmaceuticals. Because of our interest in pharmaceutical design, we recently developed a synthesis of vinyl iodides in which vinyl boronic acids are allowed to react with sodium iodide in the presence of mild oxidizing agents.⁵ The method has been successfully applied to a variety of functionally substituted, physiologically active molecules including fatty acids and steroids.⁶ We now wish to report that vinyl bromides are readily synthesized via the reaction of vinyl boronic acids with sodium bromide in the presence of mild oxidizing agents such as N-chlorosuccinimide.