Chiral bis(amino alcohol)oxalamides as ligands for asymmetric catalysis. Ti(IV) catalyzed enantioselective addition of diethylzinc to aldehydes
作者:Gonzalo Blay、Isabel Fernández、Alícia Marco-Aleixandre、José R. Pedro
DOI:10.1016/j.tetasy.2005.01.039
日期:2005.3
Several chiral bis(aminoalcohol)oxalamides with C2-symmetry have been prepared and used as ligands for the enantioselectiveaddition of diethylzinc to aromatic and aliphatic aldehydes. The reaction proceeds in the presence of titanium isopropoxide to give the corresponding (S)-alcohols with ee up to 78%. In the absence of Ti(IV), the alcohols with the opposite configuration are obtained.
Nickel-Catalyzed Enantioselective Hydroboration of Vinylarenes
作者:Hai N. Tran、Levi M. Stanley
DOI:10.1021/acs.orglett.1c04073
日期:2022.1.14
The enantioselective hydroboration of vinylarenes catalyzed by a chiral, nonracemic nickel catalyst is presented as a facile method for generating chiral benzylic boronate esters. Various vinylarenes react with bis(pinacolato)diboron (B2pin2) in the presence of MeOH as a hydride source to form chiral boronate esters in up to 92% yield with up to 94% ee. The use of anhydrous Me4NF to activate B2pin2
由手性非外消旋镍催化剂催化的乙烯基芳烃的对映选择性硼氢化反应是一种生成手性苯甲基硼酸酯的简便方法。在作为氢化物源的 MeOH 存在下,各种乙烯基芳烃与双(频哪醇)二硼(B 2 pin 2)反应形成手性硼酸酯,产率高达 92%,ee 高达 94%。使用无水 Me 4 NF 激活 B 2 pin 2对于确保快速金属转移以实现高对映选择性至关重要。