Lewis Base-Catalyzed Enantioselective Conjugate Reduction of β,β-Disubstituted α,β-Unsaturated Ketones with Trichlorosilane: <i>E</i>/<i>Z</i>-Isomerization, Regioselectivity, and Synthetic Applications
作者:Masaharu Sugiura、Yasuhiko Ashikari、Yuka Takahashi、Koki Yamaguchi、Shunsuke Kotani、Makoto Nakajima
DOI:10.1021/acs.joc.9b01298
日期:2019.9.20
The chiral bisphosphine dioxide-catalyzed asymmetric conjugate reduction of acyclic β,β-disubstituted α,β-unsaturated ketones with trichlorosilane affords saturated ketones having a stereogenic carbon center at the carbonyl β-position with high enantioselectivities. Because the E/Z-isomerizations of enone substrates occur concomitantly, reduction products with the same absolute configurations are obtained
用三氯硅烷手性双膦二氧化物催化的无环β,β-二取代的α,β-不饱和酮的不对称共轭还原,可得到在羰基β-位具有立体碳中心且具有高对映选择性的饱和酮。因为烯酮底物会同时发生E / Z-异构化,所以从(E)-或(Z)-烯。由于其碳正离子稳定能力,在烯酮的β位上存在富电子芳基的情况下,共轭还原被加速。为了阐明观察到的对映选择性的起源,还进行了计算研究。实现了二烯酮的区域和对映选择性的还原,并将其应用于ar- turmerone,turmeronol A,mutisianthol和jungianol,它们是旋光的倍半萜烯的合成。