Organocatalytic One-Pot Asymmetric Synthesis of 4H,5H‑Pyrano[2,3‑c]pyrazoles
journal contributionposted on 17.08.2012, 00:00 authored by Dieter Enders, André Grossmann, Bianca Gieraths, Muharrem Düzdemir, Carina Merkens
An efficient one pot asymmetric synthesis of tetrahydropyrano[2,3-c]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.