New Ring Expansion of Cyclobutanones: Synthesis of Pyrrolinones, Pyrrolidines and Pyrroles.

Abstract

Pyrrole derivativesPyrrole derivatives R 0120New Ring Expansion of Cyclobutanones: Synthesis of Pyrrolinones, Pyrrolidines and Pyrroles. -Ring opening of 2,2-dichlorocyclobutanones such as (I) with primary amines gives the ω,ω-dichlorobutanamides (III). They can be sequentially converted to the pharmacologically interesting pyrrole dyes in a convenient manner. -(VERNIEST, G.; BOTERBERG, S.; BOMBEKE, F.; STEVENS, C. V.; DE KIMPE*,

Highly Enantioselective Synthesis of Chiral γ-Lactams by Rh-Catalyzed Asymmetric Hydrogenation

“…Alternatively, we envisaged that β-substituted chiral γ-lactams could be directly synthesized via asymmetric hydrogenation of β-substituted α,β-unsaturated lactams (Figure , lower right). In comparison with well-established asymmetric hydrogenation of α,β-unsaturated lactones, maleinimides, and maleic anhydrides, hydrogenation of structurally similar but more inert α,β-unsaturated lactams remains a formidable task and no asymmetric manner has been developed so far. , Herein, we reported an unprecedented Rh-catalyzed asymmetric hydrogenation of β-substituted α,β-unsaturated lactams, which could successfully tolerate free NH amide group.…”