RhIII-Catalyzed Dehydrogenative Coupling of Quinoline N-Oxides with Alkenes: N-Oxide as Traceless Directing Group for Remote C–H Activation

Author： Sharma Ritika Kumar Rakesh Kumar Inder Sharma Upendra

Publisher： Blackwell Publishing

E-ISSN： 1099-0690|2015|34|7519-7528

ISSN： 1434-193X

Source： European Journal of Organic Chemistry, Vol.2015, Iss.34, 2015-12, pp. : 7519-7528

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Abstract

A Rh^III-catalyzed dehydrogenative coupling reaction of quinoline N-oxides with alkenes has been developed that provides C-8 olefinated quinoline derivatives by employing a remote C–H activation strategy. Main features of this catalytic method include the use of N-oxide as a traceless directing group, the high selectivity of the reaction for the C-8 position, and the broad scope of possible substrates. Mechanistic studies have also been performed. A five-membered rhodacycle of quinoline N-oxide, a possible key reaction intermediate, was synthesized and characterized for the first time. Remote C–H Activation: A Rh^III-catalyzed coupling reaction of quinoline N-oxides with acrylates, styrenes, and unactivated aliphatic alkenes has been developed that provides C-8 olefinated quinoline derivatives by employing a remote C–H activation strategy. A five-membered rhodacycle of quinolone N-oxide, a possible reaction intermediate, was isolated and characterized for the first time.