NHC-Catalyzed Enantioselective Synthesis of Tetracyclic δ-Lactones by (4 + 2) Annulation of <i>ortho</i>-Quinodimethanes with Activated Ketones
Deeptanu Sarkar, Shilpa Barik, Sayan Shee, Rajesh G. Gonnade, Akkattu T. Biju
Abstract
The N-heterocyclic carbene (NHC)-catalyzed generation of ortho -quinodimethanes ( o -QDMs) from 9 H -fluorene-1-carbaldehydes followed by the interception with activated ketones resulting in the enantioselective synthesis of tetracyclic δ-lactones is presented. High diastereoselectivity of products, remote C(sp 3 )–H functionalization, broad substrate scope, and mild reaction conditions are the notable features of the present (4 + 2) annulation.
Topics & Concepts
AnnulationEnantioselective synthesisChemistryCatalysisCarbeneFluoreneSubstrate (aquarium)StereochemistryCombinatorial chemistryOrganic chemistryPolymerOceanographyGeologyN-Heterocyclic Carbenes in Organic and Inorganic ChemistrySynthetic Organic Chemistry MethodsCatalytic Cross-Coupling Reactions