Diels-Alder cycloaddition carbolines

Langlois and co-workers (82CC1118 85JOC961) succeeded in the total synthesis of vindrosine (46) and vindoline (47) by the imino Diels-Alder cycloaddition using dihydro-)3-carbolines and the diene shown in Scheme 5. 

Hoomaert and colleagues synthesized a-carbolines and P-carbolinones via the intramolecular Diels-Alder cycloaddition of 2(17/)-pyrazinones (Scheme 27, equations 1, 2)... 

Imino Diels-Alder reactions.1 The cycloaddition of dihydro-p-carbolines with... 

A new and very neat synthesis of evodiamine and rutaecarpine is described by the authors as a retro mass spectral synthesis , since the original conception was derived from the mode of fragmentation of these alkaloids in the mass spectrometer this involves a familiar retro Diels-Alder fission of ring c. Evodiamine (16a) was thus constructed by a 27r + 47r cycloaddition of 3,4-dihydro-/8-carboline with the keteneimine (17), prepared in situ by elimination of sulphur dioxide from the sulphinamide anhydride (18) (Scheme 7). When the anthranilic acid derivative (19) was used the product was rutaecarpine (20) itself, the initially formed dihydro-... 

Manzatnme alkaloids can be isolated from marine sponges. They often contain p-carboline. This group has a diverse range of bioactivities. It also has its own way of establishing its structures. An intramolecular Diels-Alder reaction for manzamines has been proposed. The a is bisdihydropyridine (derived probably from amonia), and the p is an intramolecular cycloaddition in a pentacyclic structure. °° The q> is a tetracyclic intermedia, and the A is manzamine A, manzamine B, and manzamine C (Figure 2.52). 

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