(4R*,4aR*,7aS*)-5-Oxo-6-phenyl-4a,5,6,7,7a, 8-hexahydro-4H-furo[2,3-f]isoindole-4-carboxylic acid

The asymmetric unit of the title compound, C17H 15NO4, contains two independent molecules with similar geometric parameters. In both molecules, the conformation of the cyclohexene ring is half-chair, while the pyrrolidinone ring adopts an envelope conformation with the γ-carbon atom of the -pyrrolidinone ring as the flap. In the crystal, O - H⋯O hydrogen bonds between the carboxylic and carbonyl groups link alternate independent molecules into chains propagating in the b-axis direction. The crystal packing also features weak C - H⋯π interactions

(4R*,4aR*,7aS*)-5-Oxo-6-phenyl-4a,5,6,7,7a, 8-hexahydro-4H-furo[2,3-f]isoindole-4-carboxylic acid

The asymmetric unit of the title compound, C17H 15NO4, contains two independent molecules with similar geometric parameters. In both molecules, the conformation of the cyclohexene ring is half-chair, while the pyrrolidinone ring adopts an envelope conformation with the γ-carbon atom of the -pyrrolidinone ring as the flap. In the crystal, O - H⋯O hydrogen bonds between the carboxylic and carbonyl groups link alternate independent molecules into chains propagating in the b-axis direction. The crystal packing also features weak C - H⋯π interactions

The intramolecular Diels-Alder vinylthiophen (IMDAV) reaction: An easy approach to thieno[2,3-f]isoindole-4-carboxylic acids

The reaction of readily accessible 3-(thien-2-yl)allylamines with maleic anhydride, followed by a domino sequence involving successive acylation/[4+2] cycloaddition steps, leads to the formation of the thieno[2,3-f]isoindole core. The key step, the intramolecular Diels-Alder vinylaren (IMDAV) reaction, proceeds with high level of diastereoselectivity and with formation of a single diastereoisomer of the target product 4,4a,5,6,7,7a-hexahydro-3aH-thieno[2,3-f]isoindole-4-carboxylic acids in excellent yields. If the reaction is carried out at room temperature, it occurs in 2–3 days and the proton migration (H-shift) does not take place at the last stage. In boiling benzene, the reaction is complete after three hours, but in this case a slight impurity of byproducts bearing aromatic thiophene ring – 4a,5,6,7,7a,8-hexahydro-4H-thieno[2,3-f]isoindole-4-carboxylic acids is formed. © 2017 Elsevier Lt

Easy construction of furo[2,3-f]isoindole core by the IMDAV reaction between 3-(furyl)allylamines and α,β-unsaturated acid anhydrides

The vinylogues of furfurylamines, easily available in two steps from furylacroleins (3-(furyl)allylamines), were studied in a tandem N-acylation/intramolecular [4+2] cycloaddition with maleic, pyrocinchonic, and citraconic anhydrides, as well as furylacryloyl and cinnamoyl chlorides. By using a domino reaction of 3-(furyl)allylamines and α,β-unsaturated acid anhydrides under mild conditions, various hexahydro-4H-furo[2,3-f]isoindoles and their carboxyl derivatives were synthesized efficiently. The domino sequence includes three steps: acylation of the nitrogen atom in 3-(furyl)allylamines, intramolecular Diels-Alder cycloaddition in the resulting N-acyl vinylfurans (IMDAV reaction), and prototropic shift of the adducts followed by recovery of aromaticity of the furan nucleus. The key step, IMDAV reaction, leads to the target products, furo[2,3-f]isoindoles, diastereoselectively and with relatively high yields. © 2016 Elsevier Ltd. All rights reserved

The intramolecular Diels-Alder vinylthiophen (IMDAV) reaction: An easy approach to thieno[2,3-f]isoindole-4-carboxylic acids

The reaction of readily accessible 3-(thien-2-yl)allylamines with maleic anhydride, followed by a domino sequence involving successive acylation/[4+2] cycloaddition steps, leads to the formation of the thieno[2,3-f]isoindole core. The key step, the intramolecular Diels-Alder vinylaren (IMDAV) reaction, proceeds with high level of diastereoselectivity and with formation of a single diastereoisomer of the target product 4,4a,5,6,7,7a-hexahydro-3aH-thieno[2,3-f]isoindole-4-carboxylic acids in excellent yields. If the reaction is carried out at room temperature, it occurs in 2–3 days and the proton migration (H-shift) does not take place at the last stage. In boiling benzene, the reaction is complete after three hours, but in this case a slight impurity of byproducts bearing aromatic thiophene ring – 4a,5,6,7,7a,8-hexahydro-4H-thieno[2,3-f]isoindole-4-carboxylic acids is formed. © 2017 Elsevier Lt

Easy construction of furo[2,3-f]isoindole core by the IMDAV reaction between 3-(furyl)allylamines and α,β-unsaturated acid anhydrides

The vinylogues of furfurylamines, easily available in two steps from furylacroleins (3-(furyl)allylamines), were studied in a tandem N-acylation/intramolecular [4+2] cycloaddition with maleic, pyrocinchonic, and citraconic anhydrides, as well as furylacryloyl and cinnamoyl chlorides. By using a domino reaction of 3-(furyl)allylamines and α,β-unsaturated acid anhydrides under mild conditions, various hexahydro-4H-furo[2,3-f]isoindoles and their carboxyl derivatives were synthesized efficiently. The domino sequence includes three steps: acylation of the nitrogen atom in 3-(furyl)allylamines, intramolecular Diels-Alder cycloaddition in the resulting N-acyl vinylfurans (IMDAV reaction), and prototropic shift of the adducts followed by recovery of aromaticity of the furan nucleus. The key step, IMDAV reaction, leads to the target products, furo[2,3-f]isoindoles, diastereoselectively and with relatively high yields. © 2016 Elsevier Ltd. All rights reserved

The intramolecular Diels-Alder vinylfuran (IMDAV) reaction: a short approach to aza-analogues of pinguisane-type sesquiterpenes

Abstract The reaction of readily accessible (3-furyl)allylamines with maleic anhydride, followed by a domino sequence involving acylation/cycloaddition/proton shift steps, led to the formation of furo[2,3-f]isoindoles - the aza-analogs of pinguisane-type sesquiterpenes. The key intramolecular Diels-Alder vinylfuran (IMDAV) reaction proceeded under mild conditions, with high levels of diastereoselectivity and satisfactory yields. © 2015 Elsevier Ltd

The intramolecular Diels-Alder vinylfuran (IMDAV) reaction: a short approach to aza-analogues of pinguisane-type sesquiterpenes

Abstract The reaction of readily accessible (3-furyl)allylamines with maleic anhydride, followed by a domino sequence involving acylation/cycloaddition/proton shift steps, led to the formation of furo[2,3-f]isoindoles - the aza-analogs of pinguisane-type sesquiterpenes. The key intramolecular Diels-Alder vinylfuran (IMDAV) reaction proceeded under mild conditions, with high levels of diastereoselectivity and satisfactory yields. © 2015 Elsevier Ltd