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Phosphine-Mediated Iterative Arene Homologation Using Allenes.

ABSTRACT: 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 ?-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.

SUBMITTER: Zhang K

PROVIDER: S-EPMC4915745 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature

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Phosphine-Mediated Iterative Arene Homologation Using Allenes.

Zhang Kui K Cai Lingchao L Jiang Xing X Garcia-Garibay Miguel A MA Kwon Ohyun O

Journal of the American Chemical Society 20150831 35

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 mec ...[more]

PMID: 26295504

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