Non-C2-Symmetric, Chirally Economical, and Readily Tunable Linked-binols: Design and Application in a Direct Catalytic Asymmetric Mannich-Type Reaction


  • This work was supported by a Grant-in-Aid for Specially Promoted Research and a Grant-in-Aid for Encouragements for Young Scientists (B) (for S.M.) from JSPS and MEXT.


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An achiral unit is shown to be better than a chiral unit in promoting an asymmetric reaction. Non-C2-symmetric linked-binols 1 with one chiral 1,1′-bi-2-naphthol unit and one flexible achiral unit are employed as ligands in direct catalytic asymmetric Mannich-type reactions (see scheme; TON=turnover number). With as little as 0.01 mol % of ligand 1 a and 0.04 mol % of Et2Zn, the reaction proceeded smoothly to give the product in 98 % ee.