An efficient approach to isoindolo[2,1-b][2]benzazepines via intramolecular [4+2] cycloaddition of maleic anhydride to 4-α-furyl-4-N-benzylaminobut-1-enes

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• 作者：Zubkov ; Fedor I. ; Boltukhina ; Ekaterina V. ; Turchin ; Konstantin F. ; Varlamov ; Alexey V.
• 关键词：Homoallylamines ; Isoindolobenz-2-azepines ; Intramolecular Diels&ndash ; Alder reaction ; IMDAF ; Intramolecular electrophilic alkylation
• 刊名：Tetrahedron
• 出版年：2004
• 出版时间：September 13, 2004
• 年：2004
• 卷：60
• 期：38
• 页码：8455-8463
• 全文大小：189 K

文摘

Acylation of 4-α-furyl-4-<i>Ni>-benzylaminobut-1-enes with maleic anhydride gave 4-oxo-3-aza-10-oxatricyclo[5.2.1.0^1,5]dec-8-ene-6-carboxylic acid via amide formation followed by intramolecular Diels–Alder reaction of furan (IMDAF). The cycloaddition proceeded under mild reaction conditions (25°C) and provided only the <i>exoi>-adduct in quantitative yield. Treatment of this compound with PPA gave isoindolo[2,1-<i>bi>][2]benzazepine derivatives via ring opening, aromatization and intramolecular electrophilic alkylation. In order to extend the scope of the reaction sequence, 7-oxo-5,11b,12,13-tetrahydro-7<i>Hi>-isoindolo[2,1-<i>bi>][2]benzazepine-8-carboxylic acids were further transformed into useful synthetic intermediates.