Synthesis of 3-Carbamoylβ-LactamsviaManganese(III)-Promoted Cyclization ofN-Alkenylmalonamides

Access to 2-oxoazetidine-3-carboxylic acid derivatives via thermal microwave-assisted Wolff rearrangement of 3-diazotetramic acids in the presence of nucleophiles

In this work, we report an efficient approach to 2-oxoazetidine-3-carboxylic acid derivatives based on a thermally promoted Wolff rearrangement of diazotetramic acids in the presence of nucleophiles. The method allows easy variation of the substituent in the exocyclic acyl group by introducing different N-, O-, and S-nucleophilic reagents into the reaction. The reaction of chiral diazotetramic acids leads exclusively to trans-diastereomeric β-lactams. The use of variously substituted diazotetramic acids, including spirocyclic derivatives, as well as a wide range of nucleophiles provides access to a structural diversity of medically relevant 2-oxoazetidine-3-carboxylic acid amides and esters.

A new approach to the stereoselective synthesis of trans-3-carbamoyl-β-lactam moieties

Optically active 1,4-disubstituted-3-carbamoyl-azetidinones are synthesized from 5-[(N-arylamino)(hydroxyl)methylene]-2,2-dimethyl-1,3-dioxa-4,6-diones and chiral aldimines via thermal generation of carbamoyl ketenes and subsequent [2+2] cycloaddition.