Asymmetric Conjugate Reduction of α,β-Unsaturated Ketones and Esters with Chiral Rhodium(2,6-bisoxazolinylphenyl) Catalysts
作者:Yoshinori Kanazawa、Yasunori Tsuchiya、Kazuki Kobayashi、Takushi Shiomi、Jun-ichi Itoh、Makoto Kikuchi、Yoshihiko Yamamoto、Hisao Nishiyama
DOI:10.1002/chem.200500841
日期:2006.1
New asymmetric conjugate reduction of beta,beta-disubstituted alpha,beta-unsaturated ketones and esters was accomplished with alkoxylhydrosilanes in the presence of chiral rhodium(2,6-bisoxazolinylphenyl) complexes in high yields and high enantioselectivity. (E)-4-Phenyl-3-penten-2-one and (E)-4-phenyl-4-isopropyl-3-penten-2-one were readily reduced at 60 degrees C in 95 % ee and 98 % ee, respectively
在手性铑(2,6-双恶唑啉基苯基)络合物的存在下,用烷氧基氢硅烷以高收率和高对映选择性完成了β,β-二取代的α,β-不饱和酮和酯的新的不对称共轭还原。(E)-4-苯基-3-戊烯-2-酮和(E)-4-苯基-4-异丙基-3-戊烯-2-酮在60°C下容易在95%ee和98%ee中还原分别以1 mol%的催化剂负载量进行。(EtO)2MeSiH被证明是最佳的氢供体选择。(E)-β-甲基肉桂酸叔丁酯和β-异丙基肉桂酸酯也可以还原为相应的二氢肉桂酸酯衍生物,直到ee高达98%。