The synthesis of 1,4-enamino ketones has been achieved through the [3,3]-rearrangement of dialkenylhydroxylamines generated from the addition of N-alkenylnitrones to electron-deficient allenes. The mild conditions required for this reaction, and the simultaneous installation of a fluorenyl imine N-protecting group as a consequence of the rearrangement, avoid spontaneous cyclization of the 1,4-enamino ketones to form the corresponding pyrroles and allow for the isolation and controlled divergent functionalization of these reactive intermediates. The optimization, scope, and tolerance of the new method are discussed with demonstrations of the utility of the products for the synthesis of pyrroles, 1,4-diones, and furans.
Synthesis of 1,4-Enamino Ketones by [3,3]-Rearrangements of Dialkenyl-hydroxylamines. -A new method for the synthesis of 1,4-enamino ketones through rearrangement of dialkenylhydroxylamines generated in situ by addition of N-alkenylnitrones to allenes is described. This route to dialkenylhydroxylamines has a broader scope than the Trofimov reaction. Additionally, the transformation of the obtained 1,4-enamino ketones to pyrroles, 1,4-diones, and furans is also shown. -(PECAK, W. H.; SON, J.; BURNSTINE, A. J.; ANDERSON*, L. L.; Org. Lett. 16 (2014) 13, 3440-3443, http://dx.
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