Improvement in the Palladium-Catalyzed Miyaura Borylation Reaction by Optimization of the Base: Scope and Mechanistic Study

Aryl boronic acids and esters are important building blocks in API synthesis. The palladium-catalyzed Suzuki-Miyaura borylation is the most common method for their preparation. This paper describes an improvement of the current reaction conditions. By using lipophilic bases such as potassium 2-ethyl...

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Bibliographic Details
Published in:	Journal of organic chemistry Vol. 86; no. 1; p. 103
Main Authors:	Barroso, Santiago, Joksch, Markus, Puylaert, Pim, Tin, Sergey, Bell, Stephen J, Donnellan, Luke, Duguid, Stewart, Muir, Colin, Zhao, Peichao, Farina, Vittorio, Tran, Duc N, de Vries, Johannes G
Format:	Journal Article
Language:	English
Published:	United States 01.01.2021
ISSN:	1520-6904, 1520-6904
Online Access:	Get more information
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Summary:	Aryl boronic acids and esters are important building blocks in API synthesis. The palladium-catalyzed Suzuki-Miyaura borylation is the most common method for their preparation. This paper describes an improvement of the current reaction conditions. By using lipophilic bases such as potassium 2-ethyl hexanoate, the borylation reaction could be achieved at 35 °C in less than 2 h with very low palladium loading (0.5 mol %). A preliminary mechanistic study shows a hitherto unrecognized inhibitory effect by the carboxylate anion on the catalytic cycle, whereas 2-ethyl hexanoate minimizes this inhibitory effect. This improved methodology enables borylation of a wide range of substrates under mild conditions.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	1520-6904 1520-6904
DOI:	10.1021/acs.joc.0c01758