Haval–Argade contrathermodynamic rearrangement of alkylidenesuccinimides to alkylmaleimides via the corresponding isoimides: a general approach to alkyl and dialkyl substituted maleimides

Palladium-Catalyzed Domino Aminocarbonylation of Alkynols: Direct and Selective Synthesis of Itaconimides

The first direct and selective synthesis of substituted itaconimdes by palladium-catalyzed aminocarbonylation of alkynols is reported. Key to the success of this transformation is the use of a novel catalyst system involving ligand L11 and appropriate reaction conditions. In the protocol here presented, easily available propargylic alcohols react with N-nucleophiles including aryl- and alkylamines as well as aryl hydrazines to provide a broad variety of interesting heterocycles with high catalyst activity and excellent selectivity. The synthetic utility of the protocol is demonstrated in the synthesis of natural product 11 with aminocarbonylation as the key step. Mechanistic studies and control experiments reveal the crucial role of the hydroxyl group in the substrate for the control of selectivity.

Annulation of Enals with Carbamoylpropiolates via NHC-Catalyzed Enolate Pathway: Access to Functionalized Maleimides/Iso-maleimides and Synthesis of Aspergillus FH-X-213

Herein we report the N-heterocyclic carbene (NHC)-catalyzed [3 + 2] annulation of α,β-unsaturated aldehydes with carbamoylpropiolates via an unusual enolate pathway leading to the construction of highly functionalized maleimides or isomaleimides. The electronic effect imposed by the alkyl/aryl group present on the amide nitrogen of carbamoylpropiolates plays a crucial role in the selective formation of these important five-membered heterocyclic building blocks. The developed protocol is mild and tolerates a wide range of substituents on both substrates. The application of this protocol in the synthesis of the antibacterial natural product Aspergillus FH-X-213 has also been demonstrated.

General strategy for the synthesis of natural and unnatural dialkylmaleic anhydrides

Starting from alkylidenesuccinimides, a wide range of dialkylmaleic anhydrides have been synthesized via the generation of a carbanion on a succinimide unit and its condensation with various alkyl halides as the key reaction.