Carbenoid insertions into the siliconhydrogen bond catalyzed by chiral copper (I) schiff base complexes
作者:Les A. Dakin、Scott E. Schaus、Eric N. Jacobsen、James S. Panek
DOI:10.1016/s0040-4039(98)02013-9
日期:1998.12
An asymmetric insertion reaction of α-diazoesters derived from methyl arylacetates into the silicon-hydrogen bond of silanes was achieved using a copper (I) catalyst associated with a chiral, C2symmetric Schiff base. Addition of the diazoesters 1 (1 equiv) to the Cu·Lig complex (R,R)-3 (0.1 equiv) in the presence of the silane reagent (1.5 equiv) at −40° C yielded the corresponding insertion products
(Pc-L) proves capable of promoting carbene SiH bondinsertions using diazo compounds as the carbene source. This catalytic system showed broad scope and a remarkable robustness as indicated by high TON numbers (up to 30000). Moreover, the use of enynones as carbene sources proved also feasible in hydrosilane insertion using this catalytic system. Finally, the insertion in OH and NH bonds of phenols and
Enantioselective insertion reactions of methylphenyldiazoacetate into the SiH bond of silanes were effected by employing dirhodium(II) carboxylates incorporating N-phthaloyl-(S)-amino acids as chiral bridging ligands. The use of dirhodium(II) tetrakis[N-phthaloyl-(S)-phenylalaninate] as a catalyst produced methyl (2S)-(dimethylphenylsilyl)phenylacetate in 74% ee, whereas catalysis with dirhodium(II)
通过使用掺入N-邻苯二甲酰基-(S)-氨基酸作为手性桥联配体的羧酸二(II)羧酸酯实现苯基重氮乙酸甲酯对硅烷的SiH键的对映选择性插入反应。使用四[ N-邻苯二甲酰基-(S)-苯丙氨酸酯](II)作催化剂可生成74%ee的(2S)-(二甲基苯基甲硅烷基)苯乙酸甲酯,而四[ D ]-四[二]-(N-邻苯二甲酰基)催化-(S)-苯基甘氨酸盐]以72%ee得到其对映异构体。
Synthesis, Structural Analysis, and Catalytic Properties of Tetrakis(binaphthyl or octahydrobinaphthyl phosphate) Dirhodium(II,II) Complexes
The X-ray structural analyses of homoleptic Rh(II) complexes made of enantiopure (R)-1,1′-binaphthyl and (R)-(5,5′,6,6′,7,7′,8,8′-octahydro)binaphthyl phosphate ligands are for the first time presented. The possibility to introduce halogen atoms at the 3,3′-positions is also reported. The isolated dirhodiumcomplexes were further tested as catalysts (1 mol %) in enantioselective cyclopropanations and
Rhodium(I)-Catalyzed Highly Enantioselective Insertion of Carbenoid into Si–H: Efficient Access to Functional Chiral Silanes
作者:Diao Chen、Dong-Xing Zhu、Ming-Hua Xu
DOI:10.1021/jacs.5b12960
日期:2016.2.10
α-diazoesters and α-diazophosphonates has been developed. The use of a C1-symmetric chiral diene ligand enabled the asymmetric reaction to proceed under exceptionally mild conditions and give versatile chiral α-silylesters and phosphonates with excellent enantioselectivities (up to 99% ee). The mechanism and stereochemical pathway of this novel Rh(I)-carbene-directed Si-H insertion was investigated by