New developments in the functionalization of remote CH Bonds via Radical Pathways
Fabrice Dénès
University of Nantes, France
Activation of C–H bonds to form new carbon-carbon or carbon-heteroatom bonds is a very active research field in organic synthesis. In this context, translocation processes involving highly reactive radical species (e.g. alkoxyl radicals) proved to be particularly efficient.1 Because alkenyl radicals belongs to this class of highly reactive radical species they can also rearrange into new radical species, which can then undergo cyclisation to give eventually carbocyclic, or heterocyclic, compounds.2-4 We have reported in the past very efficient radical addition-translocation-cyclisation (RATC) processes mediated by heteroatom-centred radicals (S-, or P-centred radicals).5
In order to develop an efficient tool for the ”disconnection approach”, we decided to investigate further this strategy for the formation of functionalized vinylcyclopentanes (and related heterocycles). Our recent results in this field will be presented here.
(1)For selected reviews, see: (a) L. Feray, N. Kuznetsov, P. Renaud, Radicals in Organic Synthesis, Vol. 2 (Eds: P. Renaud, M. P. Sibi), Wiley-VCH, Weinheim 2001, 246; (b) J. Robertson, J. Pillai, R. K. Lush, Chem. Soc. Rev. 2001, 30, 94.
(2) Heiba, E.-A. I.; Dessau, R. M. J. Am. Chem. Soc. 1967, 89, 2238 and 3772.
(3) Curran, D. P.; Kim, D.; Liu, H. T.; Shen, W. J. Am. Chem. Soc. 1988, 110, 5900.
(4) For selected reviews on translocation processes in alkenyl radicals leading to the formation of fivemembered rings, see: (a) Renaud, P.; Beaufils, F.; Dénès, F.; Feray, L.; Imboden, C.; Kuznetsov, N. Chimia 2008, 62, 510; (b) Dénès, F.; Beaufils, F.; Renaud, P. Synlett 2008, 2389.
(5) (a) Beaufils, F.; Dénès, F.; Renaud, P. Org. Lett. 2004, 6, 2563; (b) Beaufils, F.; Dénès, F.; Beccatini, B.; Renaud, P.; Schenk, K. Adv. Synth. Catal. 2005, 347, 1587; (c) Beaufils, F.; Dénès, F.; Renaud, P. Angew. Chem. Int. Ed. 2005, 44, 5273; (d) Lamarque, C.; Beaufils, F.; Dénès, F.; Schenk, K.; Renaud. P. Adv. Synth. Catal. 2011, 353, 1353.