[3+2] Annulations between indoles and α, β-unsaturated ketones: access to pyrrolo[1,2-a]indoles and model reactions toward the originally assigned structure of yuremamine

A direct [3 + 2] annulation reaction between indoles and alpha, beta-unsaturated ketones is reported, which allows for the efficient assembly of densely substituted, highly functionalized pyrrolo[1,2-a]indoles. Model reactions toward the originally assigned structure of yuremamine are also described, leading to the successful construction of the core with required functionality.