Highly efficient enantioselective epoxidation of α,β-enones catalyzed by cheap chiral lanthanum and gadolinium alkoxides
作者:Ruifang Chen、Changtao Qian、Johannes G de Vries
DOI:10.1016/s0040-4020(01)01001-8
日期:2001.12
asymmetric epoxidation of α,β-unsaturated ketones in the presence of cumene hydroperoxide. Excellent chemical yield and enantioselectivity have been achieved for several epoxides at room temperature by using 5 mol% of La(O-i-Pr)3-(S)-6,6′-dibromo-BINOL and Gd(O-i-Pr)3-(S)-6,6′-diphenyl-BINOL, respectively. Up to 95% ee was obtained for epoxychalcone with Gd(O-i-Pr)3-(S)-6,6-diphenyl-BINOL catalyst at room
(S)-6,6'-二溴-双酚和(S)-6,6'-二苯基-双酚已被开发为适用于镧系元素在枯烯存在下催化α,β-不饱和酮的不对称环氧化的有效手性配体氢过氧化物。优异的化学产率和对映选择性已经通过使用(La中的5%(摩尔)来实现,在室温下几个环氧化物ø -我-Pr)3 - (小号)-6,6'-二溴联萘酚和Gd(ø -我-Pr )3-(S)-6,6'-二苯基-BINOL。具有Gd(O - i -Pr)3-(S)-6,6-二苯基-BINOL催化剂在室温下。还提出了合理的催化剂结构以及催化循环。