Direct asymmetric additions of ArTi(O-i-Pr)3 to aldehydes catalyzed by a titanium catalyst of (R)-H8-BINOL are reported. The reactions proceed instantaneously at room temperature, affording alcohols in ≥90% ee. Importantly, the ArTi(O-i-Pr)3 reagent differentiates the ligand effectiveness in an order of H8-BINOL > BINOL > TADDOL > diol 3 > disulfonamide 2.
报告了 ArTi(O-i-Pr)3 在 (R)-H8-BINOL 的
钛催化剂催化下与醛的直接不对称加成反应。反应在室温下瞬间进行,生成的醇的ee值≥90%。重要的是,ArTi(O-i-Pr)3 试剂可以按照 H8-BINOL > BINOL > TADDOL > 二醇 3 > 二磺酰胺 2 的顺序区分
配体的有效性。