Studies on the intramolecular oxa-Pictet–Spengler rearrangement of 5-aryl-1,3-dioxolanes to 4-hydroxy-isochromans

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• 作者：Bianchi ; Darí ; o A. ; Rú ; a ; Federico ; Kaufman ; Teodoro S.
• 关键词：oxa-Pictet&ndash ; Spengler ; isochromans ; rearrangement ; dioxolanes ; isomerization
• 刊名：Tetrahedron Letters
• 出版年：2004
• 出版时间：January 5, 2004
• 年：2004
• 卷：45
• 期：2
• 页码：411-415
• 全文大小：275 K

文摘

The success and stereochemical outcome of the TiCl₄-promoted oxa-Pictet–Spengler cyclization of 5-aryl-1,3-dioxolanes to produce 1,3-disubstituted-4-hydroxy-isochromans, is influenced by the length and nature of the side chains bound to C-2 and C-4 of the dioxolane. Methyl groups yield a mixture of 4-hydroxy-isochromans in which the 1,3-trans diastereomer predominates, while bulkier substituents give 1,3-cis diastereomers. Functional groups in the C-2 side chain of the dioxolane ring may hinder cyclization by complexation with the promoter.