An efficient synthesis of 4-ethyl-4-[(3-hydroxycarbonyl)propyl]dihydro-2(3 H)-furanone and its use in a formal total synthesis of (±)-quebrachamine
The Rh 2(OAc) 4-catalyzed reaction of diazoacetate 5 provides ready access to the pivotal cyclic acetal 13 that undergoes Pictet-Spengler-type condensation with tryptamine to directly afford an epimeric mixture of the tetracyclic lactam 17a,b. Lithium aluminum hydride reduction of 17a,b provides the...
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Published in | Tetrahedron Vol. 54; no. 44; pp. 13435 - 13448 |
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Main Authors | , |
Format | Journal Article |
Language | English |
Published |
OXFORD
Elsevier Ltd
29.10.1998
Elsevier |
Subjects | |
Online Access | Get full text |
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Summary: | The Rh
2(OAc)
4-catalyzed reaction of diazoacetate
5 provides ready access to the pivotal cyclic acetal
13 that undergoes Pictet-Spengler-type condensation with tryptamine to directly afford an epimeric mixture of the tetracyclic lactam
17a,b. Lithium aluminum hydride reduction of
17a,b provides the known tetracyclic amino alcohol
18a,b which, overall, constitutes a formal synthesis of (±)-quebrachamine.
The key intermediate
13 was derived from the γ-lactone
12 that was efficiently prepared via the dirhodium(II)-carbenoid mediated tertiary CH insertion of the appropriate diazoester. Reaction of
13 with tryptamine gave, after reduction, the known tetracycle
18. |
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ISSN: | 0040-4020 1464-5416 |
DOI: | 10.1016/S0040-4020(98)00825-4 |