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Cycloaddition of cyclobutenone and azomethine imine enabled by chiral isothiourea organic catalysts.

ABSTRACT: The addition of an organic catalyst to the ketone moiety of a ?-mono-chloride substituted cyclobutenone destroys its stable, conjugated and nearly planar structure. The C-C bond in the resulting less stable anionic oxy-substituted non-planar intermediate is then activated. The breaking of one C-C single bond leads to a catalyst-bound intermediate that undergoes ?-carbon selective reactions with azomethine imines to afford nitrogen-containing heterocyclic compounds with excellent diastereo- and enantio-selectivities. Our organocatalytic approach provides a new reaction pattern for C-C bond activation of cyclobutenones that is unavailable with transition metal catalysis. In addition, the present study with isothioureas as the organocatalysts expands the potential in using organocatalysts for C-C bond breaking and selective reactions.

SUBMITTER: Li BS

PROVIDER: S-EPMC5669243 | biostudies-literature | 2015 Oct

REPOSITORIES: biostudies-literature

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Cycloaddition of cyclobutenone and azomethine imine enabled by chiral isothiourea organic catalysts.

Li Bao-Sheng BS Wang Yuhuang Y Jin Zhichao Z Chi Yonggui Robin YR

Chemical science 20150720 10

The addition of an organic catalyst to the ketone moiety of a γ-mono-chloride substituted cyclobutenone destroys its stable, conjugated and nearly planar structure. The C-C bond in the resulting less stable anionic oxy-substituted non-planar intermediate is then activated. The breaking of one C-C single bond leads to a catalyst-bound intermediate that undergoes α-carbon selective reactions with azomethine imines to afford nitrogen-containing heterocyclic compounds with excellent diastereo- and e ...[more]

PMID: 29449914

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