Comparison of Copper(II) Acetate Promoted N-Arylation of 5,5-Dimethyl Hydantoin and Other Imides with Triarylbismuthanes and Aryl Boronic Acids
Helmut M. Hügel*, Colin J. Rix, Karin Fleck
*School of Applied Sciences (Applied Chemistry), RMIT University, GPO Box
2476V, Melbourne, Victoria 3001, Australia, Email: helmut.hugelrmit.edu.au
H. M. Hügel, C. J. Rix, K. Fleck, Synlett, 2006, 2290-2292.
DOI: 10.1055/s-2006-949638
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Abstract
Copper acetate promoted N-arylation of imides with boronic acids can be employed as a major method for the synthesis of N3-aryl hydantoins.
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Details
The document discusses the copper(II) acetate-promoted N-arylation of imides with boronic acids and triarylbismuthanes, focusing on synthesizing N3-aryl hydantoins. This method is significant for producing compounds with therapeutic applications, such as anti-convulsants and anti-androgens. The study compares the effectiveness of aryl boronic acids and triarylbismuthanes as aryl donors in these reactions.
Initial attempts using sodium hydride and aryl halides yielded poor results. Inspired by Buchwald and Hartwig's work on N-arylation, the researchers explored copper(II) acetate-mediated cross-coupling. The reactions were conducted at room temperature with imides, triaryl bismuthanes, and anhydrous solvents, yielding variable results. The best yields were obtained with N-1-naphthyl succinimide.
A comparative study using aryl boronic acids showed improved yields, attributed to the electrophilic nature of boronic acids. The document presents a potential mechanism involving the oxidation of Cu2+ to Cu3+ and subsequent reductive elimination. The study concludes that while both aryl donors are effective, boronic acids generally provide better yields due to their enhanced electrophilic character. The research highlights the importance of electronic and steric factors in the N-arylation process.
Key Words
arylations, imides, hydantoins, organoboron chemistry, organometallic reagents, Chan-Lam coupling
ID: J60-Y2006-4620