Zalibera M, Nesvadba P, Gescheidt G. Reaction of benzopinacol with non-ionic bases: reversing the pinacol coupling.
Org Lett 2013;
15:4627-9. [PMID:
24007536 DOI:
10.1021/ol402253s]
[Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The reaction of benzopinacol with the non-ionic bases butyllithium and phosphazene P4 leads to the formation of the corresponding ketyl radical anions, which have been characterized by EPR/ENDOR spectroscopy. This conversion has a high efficiency. Such a reversed pinacol reaction can be used for a controlled release of ketyl radicals. Moreover, the nature of the base has a marked effect on the association of the ketyl radical anion and the counterions. This illustrates the importance of ion pairing for reductive coupling.
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