Enantioselective Synthesis of Chromanones via a Peptidic Phosphane Catalyzed Rauhut–Currier Reaction

The enantioselective intramolecular Rauhut–Currier reaction has been developed using a bifunctional dipeptidic phosphane catalyst, providing a direct access to biologically active α-methylene-δ-valerolactones in high yields and enantiomeric excesses. The novel catalyst is accessible in only four steps from commercial sources and exhibits unusual binding selectivities for a small molecule, suggesting the possibility for long-range interactions between the catalyst and the substrate

Organocatalytic One-Pot Asymmetric Synthesis of 4<i>H</i>,5<i>H</i>‑Pyrano[2,3‑<i>c</i>]pyrazoles

An efficient one pot asymmetric synthesis of tetrahydropyrano[2,3-<i>c</i>]pyrazoles has been developed. This class of biologically active heterocycles can be obtained via a secondary amine catalyzed asymmetric Michael/Wittig/oxa-Michael reaction sequence. Remarkably, the title compounds were accessible in good to very good yields and very good to excellent enantioselectivities after a single purification step