Asymmetric Michael Addition
of Chiral Lithiated Sulfonates to Nitroalkenes: Diastereo- and Enantioselective
Synthesis of α,β-Disubstituted γ-Nitro
and β-Alkoxycarbonyl Methyl Sulfonates
作者:Dieter Enders、Otto Berner、Nicola Vignola、Wacharee Harnying
DOI:10.1055/s-2002-34368
日期:——
The diastereoselective Michael addition of lithiated enantiopure sulfonates to nitroalkenes is described. High asymmetric inductions were obtained by using 1,2:5,6-di-O-isopropylideneα-D-allofuranose as a cheap and easilyavailable chiral auxiliary. Racemization-free cleavage of the auxiliary led to α,β-disubstituted γ-nitro methyl sulfonates. A change of the cleavage conditions resulted in α,β-disubstituted
描述了锂化的对映体纯磺酸盐与硝基烯烃的非对映选择性迈克尔加成。通过使用 1,2:5,6-二-O-异亚丙基α-D-别呋喃糖作为廉价且易于获得的手性助剂获得高度不对称诱导。助剂的无外消旋裂解产生 α,β-二取代的 γ-硝基甲基磺酸盐。裂解条件的变化通过 Meyer 反应产生 α,β-二取代的 β-烷氧基羰基磺酸盐(de ≥ 98%,ee > 98%)。