Kinugasa reaction: an ‘ugly duckling’ of β-lactam chemistry

Kinugasa reactions in water: from green chemistry to bioorthogonal labelling

The Kinugasa reaction has become an efficient method for the direct synthesis of β-lactams from substituted nitrones and copper(I) acetylides. In recent years, the reaction scope has been expanded to include the use of water as the solvent, and with micelle-promoted [3+2] cycloadditions followed by rearrangement furnishing high yields of β-lactams. The high yields of stable products under aqueous conditions render the modified Kinugasa reaction amenable to metabolic labelling and bioorthogonal applications. Herein, the development of methods for use of the Kinugasa reaction in aqueous media is reviewed, with emphasis on its potential use as a bioorthogonal coupling strategy.

Recyclable organocatalyst-promoted one-pot Michael/aza-Henry/lactamization reactions for fluorinated 2-piperidinones bearing four stereogenic centres

A highly efficient method for asymmetric synthesis of fluorinated 2-piperidinones bearing four stereogenic centres is introduced.

A new mechanistic insight on β-lactam systems formation from 5-nitroisoxazolidines

DFT calculations at various theory levels unequivocally show that conversion of 5-nitroisoxazolidines into β-lactams does not take place via a ring opening step (as hitherto suggested), but takes place according to a three-step, domino-type reaction.

Diastereoselective synthesis of propargylic N-hydroxylamines via NHC–copper(i) halide-catalyzed reaction of terminal alkynes with chiral nitrones on water

The first NHC–copper(i) halide catalyzed addition of terminal alkynes to enantiomerically pure nitrones on water affording propargylic N-hydroxylamines in a highly diastereoselective fashion is reported.