AbstractA Cu‐catalyzed asymmetric synthesis of silicon‐stereogenic benzoxasiloles has been realized via intramolecular Si−O coupling of [2‐(hydroxymethyl)phenyl]silanes. Cu(I)/difluorphos is found to be an efficient catalytic system for enantioselective Si−C bond cleavage and Si−O bond formation. In addition, kinetic resolution of racemic substituted [2‐(hydroxymethyl)phenyl]silanes using Cu(I)/ PyrOx (pyridine‐oxazoline ligands) as the catalytic system is developed to afford carbon‐ and silicon‐stereogenic benzoxasiloles. Ring‐opening reactions of chiral benzoxasiloles with organolithiums and Grignard reagents yield various enantioenriched functionalized tetraorganosilanes.
摘要 通过[2-(羟甲基)苯基]硅烷的分子内Si-O偶联,实现了铜催化的苯并噁唑类硅烷的不对称合成。研究发现,Cu(I)/二氟吗啉是对映体选择性 Si-C 键裂解和 Si-O 键形成的高效催化体系。此外,利用 Cu(I)/PyrOx(吡啶-噁唑啉配体)作为催化体系,开发了外消旋取代的[2-(羟甲基)苯基]硅烷的动力学解析,从而得到碳和硅稳定的苯并噁唑。手性苯并噁唑基硅烷与有机锂和格氏试剂的开环反应生成了各种对映体富集的官能化四有机硅烷。