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Regioselective activation of benzocyclobutenones and dienamides lead to anti-Bredt bridged-ring systems by a [4+4] cycloaddition.

ABSTRACT: To the best of our knowledge, bridgehead carbon benzofused-bridged ring systems have previously not been accessible to the synthetic community. Here, we describe a formal type-II [4 + 4] cycloaddition approach that provides fully sp²-carbon embedded anti-Bredt bicyclo[5.3.1] skeletons through the Rh-catalyzed C₁-C₈ activation of benzocyclobutenones (BCBs) and their coupling with pedant dienamides. Variously substituted dienamides have been coupled with BCBs to provide a range of complex bicyclo[5.3.1] scaffolds (>20 examples, up to 89% yield). The bridged rings were further converted to polyfused hydroquinoline-containing tetracycles via a serendipitously discovered transannular 1,5-hydride shift/Prins-like cyclization/Schmidt rearrangement cascade.

SUBMITTER: Zhang J

PROVIDER: S-EPMC8140143 | biostudies-literature | 2021 May

REPOSITORIES: biostudies-literature

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Regioselective activation of benzocyclobutenones and dienamides lead to anti-Bredt bridged-ring systems by a [4+4] cycloaddition.

Zhang Jianyu J Wang Xi X Xu Tao T

Nature communications 20210521 1

To the best of our knowledge, bridgehead carbon benzofused-bridged ring systems have previously not been accessible to the synthetic community. Here, we describe a formal type-II [4 + 4] cycloaddition approach that provides fully sp2-carbon embedded anti-Bredt bicyclo[5.3.1] skeletons through the Rh-catalyzed C1-C8 activation of benzocyclobutenones (BCBs) and their coupling with pedant dienamides. Variously substituted dienamides have been coupled with BCBs to pr ...[more]

PMID: 34021154

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