Applications of Thermal and Microwave-Assisted Cyclization in the Synthesis of Baylis–Hillman-Derived Heteropolycyclic Systems

Abstract

Baylis–Hillman reactions of pyridine-2- and quinoline-2-carbaldehydes with chromone derivatives, using tetramethylpropylenediamine in tetrahydrofuran (THF)–H₂O, afford convenient access to adducts, cyclization of which leads to the corresponding tetra- and pentacyclic products. The relative efficiencies of thermal and microwave-assisted cyclization approaches have also been examined.

Keywords:

• Baylis–hillman reaction
• heteropolycyclic systems
• microwave-assisted cyclization

ACKNOWLEDGMENTS

We are grateful to the National Research Foundation (NRF: GUN 2069255) for a bursary (M.M.G.) and to the Medical Research Council of South Africa (MRC) and Rhodes University for generous financial support. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the authors, and therefore the NRF does not accept any liability in regard thereto.