Pericyclic Cascade Reactions Affording Thienyl- and Benzo[b]thienyl-Fused Architectures: A Synthetic and Density Functional Theory Analysis of Asynchronous Diels–Alder Reactions of Thioarylmaleimides

Abstract

Herein, we report the synthesis and characterization of a series of thioarylmaleimides and their varied propensity toward highly selective domino Diels−Alder (D−A)/rearrangement, D− A/ene/elimination, and D−A/oxidation reactions to give three types of thienyl-fused architectures. Stereochemical assignment was achieved using a combination of nuclear magnetic resonance (NMR) studies, gauge independent atomic orbital (GIAO) NMR chemical shift calculations, and DP4+ analysis. Transition-state calculations support an asynchronous concerted mechanism and provide support for rationalizing the observed regio-and stereoselectivity.

Application of the intramolecular Diels–Alder vinylarene (IMDAV) reaction for the synthesis of benzo-, carbocyclo-, thienothiopheneisoindolecarboxylic acids and its limitations

“…Moreover, annulated thiophenes and their derivatives react both as dienes and dienophiles. 4,5 But as far as we are concerned, there is only one publication to date related to the intramolecular Diels–Alder reaction of benzo[ b ]thiophene derivatives that demonstrates the fundamental possibility of IMDAV (intramolecular Diels–Alder vinylarene) 6 transformations in the benzothiophene series; 7 for cycloalkyl- and thienothiophenes such cases are not known. Earlier, based on the tandem acylation/IMDAV strategy, we proposed the original synthesis of isoindoles fused with various cycles (Fig.…”