Rapid and Facile Synthesis of Isomaleimides: Dehydration of Maleamic Acids using Methanesulfonyl Chloride
作者:Mitchell P. Croatt、Khyarul Alam、Elvis C. McFee
DOI:10.1055/s-0041-1737414
日期:2022.7
The dehydration of maleamicacids using methanesulfonyl chloride as a dehydrating agent to selectively and rapidly (<15 min) generate isomaleimides is reported. A variety of maleamicacid derivatives produce the corresponding isomaleimides in good to excellent yields. Adaptation of this protocol under flow synthesis allows for similar efficiency and decreased reaction times (13 seconds residence time)
Base-catalyzed asymmetric cycloaddition of anthrone with achiral and chiral N-substituted maleimides was carried out in the presence of C-2-chiral pyrrolidines in almost quantitative yields. Chiral, non-racemic [4+2] adducts up to 61% ee were produced with achiral N-methyl and N-benzylmaleimide using the chiral catalysts. De's of the adducts up to 38% were observed in the cases of chiral N-substituted maleimides and achiral pyrrolidine, in which the absolute configuration of the major product was established by X-ray analysis. The combination of chiral maleimides and chiral catalysts afforded the adducts having up to 80% de. (C) 1997 Published by Elsevier Science Ltd. All rights reserved.
Synthesis and reactivity of (1S)-N-(1-phenylethyl)maleimide towards nucleophiles: an application to preparation of chiral pyrroloisothiochroman and pyrrolobenzo[d]thiepine based on π-cationic cyclization
Chiral pyrroloisothiochroman and pyrrolo[d]thiepine were obtained efficiently in four steps from N-alkylated maleimides via, successively, sulfurization, regioselective reduction followed by pi -cationic cyclination of the N-acyliminium ion intermediates. These latter, in addition, led to conjugate enamides as a consequence of the dehydration reaction. (C) 2001 Elsevier Science Ltd. All rights reserved.