An Approach toward Isoindolobenzazepines Using the Ammonium Ylide/Stevens [1,2]-Rearrangement Sequence
| Autor: | Kimberly J. Worsencroft, Beall Ls, Cheryl K. Eidell, Albert Padwa |
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| Rok vydání: | 2001 |
| Předmět: | |
| Zdroj: | The Journal of Organic Chemistry. 66:2414-2421 |
| ISSN: | 1520-6904 0022-3263 |
| DOI: | 10.1021/jo001684w |
| Popis: | Ammonium ylides derived from the Cu(II)-catalyzed decomposition of α-diazo carbonyls tethered to tertiary amines underwent a benzylic Stevens [1,2]-rearrangement to give tetrahydroisoquinolines or benzazepines containing fused five-membered rings, a feature found in the cephalotaxus alkaloids. Model studies were also carried out toward the synthesis of lennoxamine, a member of the isoindolobenzazepine family of alkaloids. The approach utilized is based on the Rh(II)-catalyzed reaction of an α-diazo carbonyl compound containing an amido group in the γ-position. Treatment of several N,N-dialkyl-substituted amido diazo-esters with Rh2(OAc)4 in benzene at 80 °C in the presence of several dienophiles gave [4 + 2]-cycloadducts derived from the Diels−Alder reaction of a transient α-amino isobenzofuran intermediate. In the absence of an external trapping agent, no rearranged product derived from an ammonium ylide intermediate could be detected in the crude reaction mixture. In contrast to this result, reaction of... |
| Databáze: | OpenAIRE |
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