Reaction of 2-Benzoyl-1,2-Dihydroisoquinaldonitrile Hydrofluoroborate Salt with some 1,4-Quinones

Reaction of 2-Benzoyl-1,2-Dihydroisoquinoline-1-Carbonitrile Tetrafluoroborate Salt with 2-Arylmethylene-1,3-Indanediones. Regio- and Stereochemistry of the Reaction. Formation of Spiro Compounds

“…The tetrafluoroborate 4 (R = Ph) was prepared according to the literature. [2][3][4][5] 2-Benzylidene-1,3-indanediones 6: These compounds were obtained by an adaptation of a published procedure. 7 General procedure: 1,3-Indanedione {20 mmoles) and the arylaldehyde (20 mmol) in toluene (50 ml) were refluxed 24 hrs with a catalytic amount of p-toluenesulfonic acid, removing water using a Dean-Stark apparatus.…”

“…Moreover, the observation of a long range coupling 4 J = 0.90 -1.45 Hz between OH and H 4 allows us to propose a trans-pseudoaxial conformation for OH and H 4 in order to attain the W disposition. [4][5][6] This proposition was confirmed on the one hand by a decoupling double-irradiation experiment, and on the other hand by the disappearance of the signal of the OH proton after addition of D 2 O, whereupon the signal of the H 4 proton became a singlet. It is in good agreement with the more thermodynamically stable trans-disubstitution for the two 4-and 5-aryl groups.…”

“…[2][3][4] As a part of the research of our group on the reactivity of the tetrafluoroborate salts of Reissert compounds, [3][4][5] we report here the reaction of a tetrafluoroborate salt 1-4 (R = Ph) with some 2-arylmethylene-1,3-indanediones 6a-d. To our knowledge, the only published study of the dienophilic reactivity of enones with a Reissert salt was our own previous report. 4 According to the results of McEwen et al 2 and to previous work of our group, 3-5 spiro[4-aryl-5-hydroxy-2-(1-isoquinolinyl)-5-phenyl-4,5-dihydro-3H-pyrrole-3:2'-1',3'-indanediones] 9 result from the initial Diels-Alder reaction of the heterodiene 4 (R = Ph), followed by a rearrangement sequence involving the intermediate species 7 and 8 (Scheme 2).Determination of the structure of compounds 9 has enabled us to establish the regio-and stereochemistry of the reaction. The regiochemistry of the reaction corresponds to that which is usually observed 2-5 in the case of a dienophilic alkene activated by an electron-withdrawing group: this group is always…”

3‐Arylidene‐4‐Chromanones and 3‐Arylidene‐4‐Thiochromanones: Versatile Synthons towards the Synthesis of Complex Heterocycles

“…Although the formation of spirochromanones 68 in the above mentioned reaction can be visualised as a [4+2] cycloaddition involving the in‐situ generated oxazole tetrafluoroborate salt and arylidene chromanone, there are reports that the reaction of such tetrafluoroborate salts with α , β ‐unsaturated ketones are actually 1,3‐dipolar cycloaddition reaction and not Diels‐Alder reaction [82] . The structure of the spiro[chromane‐3,3′‐pyrrol]‐4‐ones 68 was confirmed by NMR spectral data.…”

Synthesis of Benzo[f]isoindole-4,9-diones

“…Although these benzo[ f ]isoindole-4,9-diones 1 have attracted considerable attention in the literature, only a limited number of synthetic pathways were developed toward compounds having a benzo[ f ]isoindole-4,9-dione core. These pathways are mainly based upon 1,3-dipolar cycloaddition of pyridinium or isoquinolinium ylids across 1,4-naphthoquinones, 1,3-dipolar cycloadditions of azomethine ylids generated from amino acids or nitrile oxides, via an unusual rearrangement of 2,3-diacetylenyl-1,4-naphthoquinone with hydrazide, starting from the annelated thiophenes and a photochemical addition of 2,3-diphenyl-2 H -azirine to 1,4-naphthoquinone . The synthesis of 2-methyl-2 H -benzo[ f ]isoindole-4,9-dione is based on the nucleophilic displacement of both methylthio groups in 2,3-bis(methylthiomethyl)-1,4-naphthoquinone with methylamine, followed by oxidation by oxygen to afford the benzo[ f ]isoindole .…”