ORGN 946 |
| Isoxazoles have long been recognized as versatile synthetic intermediates for the construction of 1,3-difunctionalized compounds. Previously, we demonstrated that 3-bromoisoxazoles and 3-carboxyisoxazoles can undergo ring opening to yield 2-ketonitriles. The enolates derived from these ketonitriles have been shown to undergo a variety of condensation reactions with carbonyl compounds. Recently, we have shown that with the appropriate substrate, an isoxazole with a tethered carbonyl group, these two reactions can be used in tandem, in a one-pot ring opening/cyclization sequence. Herein, we wish to report on the successful application of this methodology using both 3-bromoisoxazoles and 3-carboxyisoxazoles as precursors for the synthesis of a series of functionalized 5, 6 and 7-membered carbocycles. In addition, we will report on the application of these isoxazoles to the synthesis of oxacycles, with particular emphasis on a series of substituted benzoxepins, whose parent ring structure is found in number of biologically active natural products. |
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New Reactions and Methodology
1:00 PM-5:00 PM, Thursday, 14 September 2006 Moscone Center -- Room 133, Oral
Division of Organic Chemistry |