Phosphine-Mediated Iterative Arene Homologation Using Allenes

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• 作者：Kui Zhang ; Lingchao Cai ; Xing Jiang ; Miguel A. Garcia-Garibay ; Ohyun Kwon
• 刊名：Journal of the American Chemical Society
• 出版年：2015
• 出版时间：September 9, 2015
• 年：2015
• 卷：137
• 期：35
• 页码：11258-11261
• 全文大小：424K
• ISSN：1520-5126

文摘

A PPh₃-mediated multicomponent reaction between o-phthalaldehydes, nucleophiles, and monosubstituted allenes furnishes functionalized non-C₂-symmetric naphthalenes in synthetically useful yields. When the o-phthalaldehydes were reacted with 1,3-disubstituted allenes in the presence of PPh₂Et, naphthalene derivatives were also obtained in up to quantitative yields. The mechanism of the latter transformation is straightforward: aldol addition followed by Wittig olefination and dehydration. The mechanism of the former is a tandem 纬-umpolung/aldol/Wittig/dehydration process, as established by preparation of putative reaction intermediates and mass spectrometric analysis. This transformation can be applied iteratively to prepare anthracenes and tetracenes using carboxylic acids as pronucleophiles.