Ruthenium(ii)-catalyzed regioselective 1,6-conjugate addition of umpolung aldehydes as carbanion equivalents |
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Authors: | Hyotaik Kang Chao-Jun Li |
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Institution: | Department of Chemistry, FRQNT Centre for Green Chemistry and Catalysis, McGill University, 801 Sherbrooke St. W., Montréal Québec H3A 0B8 Canada, |
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Abstract: | One of the most efficient and reliable approaches to construct C–C bonds involves the conjugate addition of carbon nucleophiles to electron-deficient ketones. Yet, 1,6-conjugate additions of extended conjugated systems largely remain underexplored due to difficulties in controlling the regioselectivity. Herein, we report umpolung aldehydes as carbanion equivalents for highly regioselective 1,6-conjugate addition reactions to unsaturated ketones, with preliminary studies of the enantioselective variant. The synergy of ruthenium(ii) catalyst and electron-rich, bidentate phosphine ligand is essential for the reactivity and selectivity under mild reaction conditions.Highly regioselective 1,6-conjugate addition was developed using hydrazone as carbanion equivalent catalyzed by ruthenium under mild conditions. |
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