ORGN 956 |
| Conjugated nitroalkenes are powerful Michael acceptors and the addition of various C, N, O and S-centered nucleophiles to nitroalkenes is often a convenient initiating step for the synthesis of complex multi-functional molecules. Our studies on the reaction of a series of b-substituted nitroethylenes 1 with bromoform mediated by Mg or LDA showed that products 2 arising from conjugate addition of tribromomethyl carbanion to nitroalkenes 1 can be isolated in moderate to high yields. Interestingly, the novel Michael type adducts 2 underwent elimination of HBr to afford 3. Although tribromides 2 were isolated and characterized, a one-pot transformation of 1 to 3 was feasible by appropriate choice of the amount of reagents and reaction conditions. Structures of both 2 and 3 were unambiguously established by single crystal X-ray analysis. This strategy offers the possibility of transforming 2 into b-amino acids and 3 into propargylated nitro compounds.
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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 |
