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

Here we report Pd(0)-catalysed asymmetric inverse-electron-demand oxa-Diels-Alder reactions between the carbonates of 4-hydroxy-2-cyclopentenones and alpha-cyano chalcones by in situ generating eta(2)-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 alpha,beta-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.