Palladium-catalysed diastereodivergent inverse-electron-demand oxa-Diels–Alder reactions of in situ formed cyclopentadienones via ligand-control

Abstract

Here we report Pd(0)-catalysed asymmetric inverse-electron-demand oxa-Diels–Alder reactions between the carbonates of 4-hydroxy-2-cyclopentenones and α-cyano chalcones by in situ generating η²-Pd(0)-cyclopentadienone complexes as HOMO-raised dienophiles, and diastereodivergent synthesis could be realised by employing a bifunctional monophosphine ligand from a chiral aminoalcohol or a proline-derived bisphosphine ligand. More types of α,β-unsaturated carbonyls have also been successfully used as 1-oxadiene partners, furnishing a range of chiral fused dihydropyrans with versatile structural and functional diversity, generally with high stereoselectivity.