ORGN 711 |
| The piperidone ring system is a common structural motif found in a wide array of alkaloid families and is often employed as a synthetic intermediate for the construction of complex azapolycycles. As part of our efforts to develop a general method toward the construction of different alkaloid classes, we have been involved in a study of the conjugate addition of oximes to divinylsulfones followed by a [3+2]-cycloaddition of the resulting nitrone as a method for constructing functionalized piperidone ring systems. Thus, the conjugate addition of an oxime to 2,3-bis(phenylsulfonyl)-1,3-butadiene generates a transient Z-nitrone which readily undergoes a subsequent intramolecular [3+2]-cycloaddition across the tethered pi-bond. Reductive N-O cleavage of the resulting dipolar cycloadduct provides a functionalized piperidone ring system that can be further manipulated in subsequent steps. Several examples of this methodology will be presented in the context of a variety of alkaloid scaffolds. |
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Heterocycles and Aromatics
8:00 AM-12:00 PM, Thursday, 1 September 2005 Washington DC Convention Center -- Ballroom B, Oral
Division of Organic Chemistry |