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Hypervalent Activation as a Key Step for Dehydrogenative ortho CC Coupling of Iodoarenes
Author(s) -
Wu Yichen,
Arenas Ismael,
Broomfield Lewis Marc,
Martin Eddy,
Shafir Alexandr
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201503987
Subject(s) - hypervalent molecule , chemistry , reagent , substituent , combinatorial chemistry , ketone , catalysis , iodine , medicinal chemistry , organic chemistry
Building on earlier results, a direct metal‐free α‐ arylation of substituted cyclic 1,3‐diones using ArI(O 2 CCF 3 ) 2 reagents has been developed; unlike other arylative approaches, the arylated products retain the iodine substituent ortho to the newly formed CC bond. The mechanism is explored by using DFT calculations, which show a vanishingly small activation barrier for the CC bond‐forming step. In fact, taking advantage of an efficient in situ hypervalent activation, the iodoarenes are shown to undergo a cross‐ dehydrogenative CC coupling at the CH ortho 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) 2 species and the sulfate‐accelerated final coupling with a ketone. This method complements the ipso selectivity obtained in the metal‐catalyzed α‐arylation of carbonyl compounds.