Hypervalent Activation as Key Step for Dehydrogenative ortho C-C Coupling of Iodoarenes
<p> Building on earlier results, a direct metal-free α- arylation of substituted cyclic 1,3-diones using ArI(O<sub><font size="2">2</font></sub>CCF<sub><font size="2">3</font></sub>)<sub><font size="2&q...
| Authors: | , , , , |
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| Format: | article |
| Publication Date: | 2015 |
| Country: | España |
| Institution: | Varias* (Consorci de Biblioteques Universitáries de Catalunya, Centre de Serveis Científics i Acadèmics de Catalunya) |
| Repository: | Recercat. Dipósit de la Recerca de Catalunya |
| OAI Identifier: | oai:recercat.cat:2072/305930 |
| Online Access: | http://hdl.handle.net/2072/305930 https://doi.org/10.1002/chem.201503987 |
| Access Level: | Open access |
| Keyword: | arylation C-H functionalization cross-coupling cross-dehydrogenative coupling hypervalent iodine |
| Summary: | <p> Building on earlier results, a direct metal-free α- arylation of substituted cyclic 1,3-diones using ArI(O<sub><font size="2">2</font></sub>CCF<sub><font size="2">3</font></sub>)<sub><font size="2">2</font></sub> reagents has been developed; unlike other arylative approaches, the arylated products retain the iodine substituent <em>ortho</em> to the newly formed C-C bond. The mechanism is explored by using DFT calculations, which show a vanishingly small activation barrier for the C-C bond-forming step. In fact, taking advantage of an efficient in situ hypervalent activation, the iodoarenes are shown to undergo a cross- dehydrogenative C-C coupling at the C-H <em>ortho</em> to the iodine. When Oxone is used as terminal oxidant, the process is found to benefit from a rapid initial formation of the hypervalent ArI(OR)<sub><font size="2">2</font></sub> species and the sulfate-accelerated final coupling with a ketone. This method complements the <em>ipso</em> selectivity obtained in the metal-catalyzed α-arylation of carbonyl compounds.</p> |
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