Formation of 6-Azaindoles by Intramolecular Diels–Alder Reaction of Oxazoles and Total Synthesis of Marinoquinoline A
Mana Osano, Dishit P. Jhaveri, Peter Wipf
Abstract
A new variant of the intramolecular Diels–Alder oxazole (IMDAO) cycloaddition that provides direct access to 6-azaindoles was developed. The IMDAO reaction was applied in a total synthesis of the aminophenylpyrrole-derived alkaloid marinoquinoline A, also featuring the use of a Curtius reaction for preparation of a 5-aminooxazole, a propargylic C,H-bond insertion, an in situ alkyne–allene isomerization, and a ruthenium-catalyzed cycloisomerization for benzene ring annulation to the 6-azaindole.
Topics & Concepts
ChemistryOxazoleIntramolecular forceAnnulationCycloisomerizationCycloadditionDiels–Alder reactionIsomerizationAromatizationRing (chemistry)Total synthesisAlleneCurtius rearrangementAlkyneRutheniumMedicinal chemistryCatalysisStereochemistryOrganic chemistryChemical synthesis and alkaloidsAsymmetric Synthesis and CatalysisMarine Sponges and Natural Products