Haval–Argade contrathermodynamic rearrangement of alkylidenesuccinimides to alkylmaleimides via the corresponding isoimides: a general approach to alkyl and dialkyl substituted maleimides
摘要:
A simple and efficient access to alkyl and dialkyl substituted maleimides has been demonstrated via the new contrathermodynamic rearrangement of (E)-alkylidenesuccinimides to alkylinaleimides. The (E)-alkylidenesuccinimides obtained from the Wittig-condensation of N-arylmaleimide with aliphatic aldehydes oil regioselective hydrolysis furnished the corresponding (E)-alkylidenesuccinanilic acids in 95-98% yields. The beta-alkylidenesuccinanilic acids oil treatment with cyanuric chloride in the presence of triethylamine gave the corresponding beta-alkylisomaleimides in 78-80% yields via the beta-alkylideneisosuccinimides with the exocyclic to endocyclic carbon-carbon double bond migration. The kinetically controlled products alkylisomaleimides in refluxing acetic acid furnished the thermodynamically controlled alkylinaleimides in 98% yield. The Wittig condensation of alkyl substituted isomaleimides/maleimides with aliphatic aldehydes gave the desired dialkyl substituted maleimides in high yields. A conversion of alpha-methylenesuccinanilic acids to alpha-methylisomaleimides has also been described, with 90% yield. (c) 2006 Elsevier Ltd. All rights reserved.
Sonogashira Coupling Reactions of Bromomaleimides: Route to Alkyne/cis-Alkene/Alkyl Maleimides: Synthesis of Luffarin X and Cacospongionolide C
摘要:
Palladium-catalyzed Sonogashira coupling reaction of bromomaleimides with a diverse range of terminal alkynes has been demonstrated to furnish the corresponding alkynylmaleimides in very good yields. This coupling reaction followed by selective reduction of the triple bond to single bond have been utilized as the decisive steps to accomplish the first total synthesis of natural products (+/-)-luffarin X and (+/-)-cacospongionolide C.