The Selective Cross-Coupling of Secondary Alkyl Zinc Reagents to Five-Membered-Ring Heterocycles Using Pd-PEPPSI-IHept super(Cl)
The ability to cross-couple secondary alkyl centers is fraught with a number of problems, including difficult reductive elimination, which often leads to beta -hydride elimination. Whereas catalysts have been reported that provide decent selectivity for the expected (non-rearranged) cross-coupled pr...
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Published in | Angewandte Chemie Vol. 127; no. 33; pp. 9638 - 9642 |
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Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
01.08.2015
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Subjects | |
Online Access | Get full text |
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Summary: | The ability to cross-couple secondary alkyl centers is fraught with a number of problems, including difficult reductive elimination, which often leads to beta -hydride elimination. Whereas catalysts have been reported that provide decent selectivity for the expected (non-rearranged) cross-coupled product with aryl or heteroaryl oxidative-addition partners, none have shown reliable selectivity with five-membered-ring heterocycles. In this report, a new, rationally designed catalyst, Pd-PEPPSI-IHept super(Cl), is demonstrated to be effective in selective cross-coupling reactions with secondary alkyl reagents across an impressive variety of furans, thiophenes, and benzo-fused derivatives (e.g., indoles, benzofurans), in most instances producing clean products with minimal, if any, migratory insertion for the first time.Original Abstract: Die Kreuzkupplung unterschiedlicher Fuenfring-Heterocyclen mit sekundaeren Alkylzinkreagentien wird durch den neuen Praekatalysator Pd-PEPPSI-IHept super(Cl) ermoglicht, der ein sterisch anspruchsvolles N-heterocyclisches Carben traegt. Der Katalysator verhindert migratorische Insertionsreaktionen (Umlagerungen), und die gewuenschten Produkte werden mit hoher Selektivitaet gebildet. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 content type line 23 ObjectType-Feature-2 |
ISSN: | 0044-8249 1521-3757 |
DOI: | 10.1002/ange.201503941 |