Aromatics to bis-triquinane: a tandem oxidative dearomatization of bis-phenol, cycloaddition, photorearrangement and a rapid entry into carbocyclic framework of Xeromphalinone E

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• 作者：Deepak Singh ; Umesh V. Chaudhari ; Pradeep T. Deota ; ^{deotapt@yahoo.com" class="auth_mail}
• 关键词：Bis-triquinane ; Oxidative dearomatization ; ODPM rearrangement ; Photoaromatization
• 刊名：Tetrahedron
• 出版年：29 July 2014
• 年：2014
• 卷：70
• 期：30
• 页码：4485-4493
• 全文大小：778 K

文摘

A novel approach for the synthesis of a bird-shaped bis-triquinane 3, a fascinating carbocyclic framework closely related to the skeleton of Xeromphalinone E 1 from readily available 2,6-dimethyl phenol 8 has been reported. The synthesis of bis-cyclohexadienones 6, 22a–e by oxidative acetylation of tetramethyl bisphenols 7, 20a–e has been investigated using two different reagents under varying reaction conditions. The cycloaddition of bis-cyclohexadienone 6 gives two carbocycles, bis-adduct 4b and mono-adduct 5d in a stereocontrolled manner. The photochemical sigmatropic 1,2-acyl shift in 4b furnished 3 and monotriquinane 9 linked with a 9-acetoxy-9-methyl-endo-tricyclo[5,2,2,0^2,6]undeca-4,10-diene-8-one system. Two different pentasubstituted phenols 13 and 14 were also isolated during an attempted oxa-di-蟺-methane (ODPM) rearrangement of mono-adduct 5d via aromatisation of the cyclohexadienone ring. The photochemical behaviour of bis-cyclohexadienones 6, 22a–e has also been investigated under UV irradiation and two different aromatized products were isolated for each bis-cyclohexadienone by migration and elimination of acetate groups.