14997-05-8Relevant articles and documents
Synthesis of aspidodispermine via pericyclic framework reconstruction
Reu?, Franziska,Heretsch, Philipp
, p. 3956 - 3959 (2020/05/19)
A divergent approach to the pyrroloquinoline scaffold as present in the class of Aspidosperma alkaloids was developed. As a case study, abundant and renewable nicotinic acid was transformed via pericyclic framework reconstruction into aspidodispermine, a unique member of pyrroloquinoline alkaloids. The sequence comprises a [2 + 2]-photocycloaddition, a Ramberg-B?cklund contraction, and a strain-promoted formal electrocyclic rearrangement of a bicyclo[2.2.0]hexene and is potentially extendable to pyrroloindole scaffolds as present in the ibophyllidine alkaloids.
Towards a new synthetic entry into the Iboga-alkaloid family
Frauenfelder, Christine,Borschberg, Hans-Juerg
, p. 1753 - 1765 (2007/10/03)
A novel retrosynthetic concept is presented that, in principle, allows access to many hitherto not accessible representatives of the Iboga-alkaloid family. The flexibility required by this approach is provided through a highly convergent assembly of the target, which allows for a control over the substitution pattern of the indole sub-system, as well as over the relative configuration of the aliphatic core of these alkaloids. The key step for the construction of the latter consists in an intramolecular nitrone-olehn 1,3-dipolar cycloaddition reaction of 26 to yield the crucial tricyclic isoxazolidine derivative 28.
