An efficient one-pot synthesis of polysubstituted pyrrolizines from N-vinyl-α,β-unsaturated nitrones and activated alkynes through iron­(III)/copper­(II)-cocatalyzed [3 + 2] cycloaddition/[3,3]-rearrangement and sequential N–O bond cleavage was developed. The reaction first underwent [3 + 2] cycloaddition and [3,3]-rearrangement to afford nine-membered N-heterocycles, and then a controlled N–O bond cleavage of nine-membered rings by iron­(III)/copper­(II) cocatalysts delivered pyrrolizine scaffolds. A kinetic resolution of nine-membered ring compounds was achieved for the first time by using copper­(II) acetate combined with a chiral PyBox ligand.

Amides are essentially inert carboxyl derivatives in many types of chemicalt ransformations.I np articular,d eoxygenative CÀCb ond formation of amides to synthetically important amines is al ong-standing challenge for synthetic chemists due to the inertness of the resonance-stabilized amide C = Ob ond. Herein, it is disclosed that by merging electrontransfer-induced activation with 1,2-metalate rearrangement, awide range of aromatic amides react smoothly with arylboron reagents,a ffording as eries of biologically relevant diarylmethylamines as deoxygenative CÀCb ond cross-coupling products.Withits simplicity and versatility,this reaction shows great promise in the synthesis of amines from amides,w hich may open up new avenues in retrosynthetic planning and find widespread use in academia and industry.Scheme 1. Merging electron transfer with 1,2-metalate rearrangement for the deoxygenative functionalization of amides.

A metal-free construction of highly diastereoselective nine-membered heterocycles is described via the cycloaddition and rearrangement of N-vinyl-a,b-unsaturated ketonitrones and isocyanates. Notably, the prepared nine-membered heterocycles afforded 2,3-dihydropyrrolizines under heating conditions. Mechanistic studies showed that the nine-membered rings might undergo decarboxylation, isomerization, aza-Michael addition, and aromatization to afford 2,3-dihydropyrrolizines in a one-pot reaction.