A novel trinuclear titanium(IV) complex with a C3 axis along Ti1–Ti2–Ti3 containing 3-[(1H-1,2,4-triazol-1-yl)methyl]-BINOLate ligands: synthesis, structure, and reactivity

A new modified BINOL, (S)-3-[(1H-1,2,4-triazol-1-yl)methyl]-1,1′-binaphthol, was prepared. In the presence of titanium tetraisopropoxide, this ligand showed moderate catalytic properties for the asymmetric addition of diethylzinc to aldehydes. By treating rac-3-[(1H-1,2,4-triazol-1-yl)methyl]-1,1′-binaphthol with excess titanium tetraisopropoxide, a novel trinuclear titanium(IV) complex was obtained. A C3 axis along Ti1–Ti2–Ti3 is present in the molecule.

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(S)-3-[(1H-1,2,4-Triazol-1-yl)methyl]-2,2′-bis(methoxymethyl)-1,1′-binaphtholC27H25N3O4Ee = 100%[α]D25=-56.6 (c 1.4, CH2Cl2)Source of chirality: resolutionAbsolute configuration: S

(S)-3-[(1H-1,2,4-Triazol-1-yl)methyl]-1,1′-binaphtholC23H17N3O2Ee = 100%[α]D25=-29.3 (c 0.3, CH2Cl2)Source of chirality: resolutionAbsolute configuration: S