An efficient synthesis of 4-ethyl-4-[(3-hydroxycarbonyl)propyl]dihydro- 2(3h)-furanone and its use in a formal total synthesis of (±)-quebrachamine

Article abstract of DOI:10.1016/S0040-4020(98)00825-4

The Rh₂(OAch)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.