D-甘露醇衍生的新型手性硫脲的合成及其在Henry反应中的应用

以D-甘露醇为原料，经缩合，醇解，叠氮化和还原等4步反应制得含联1,3-二氧六环骨架的手性胺中间体(4)； 4分别与3,5-双(三氟甲基)苯基异硫氰酯，表奎宁异硫氰酸酯和表奎尼丁异硫氰酸酯偶联合成了3个新型的手性硫脲(6a~6c)，其结构经¹H NMR, ¹³C NMR, IR和HR-MS表征。以硝基甲烷和苯甲醛的不对称Henry反应为探针反应，考察了6的催化活性。结果表明：在以吡啶为碱，甲苯为溶剂，6b 5%(摩尔百分数)，于-30 ℃反应24 h的条件下，(S)-2-硝基-1-苯基乙醇的收率和对映选择性分别为69%和78%。

Synthesis of Novel Chiral Thioureas Derived from D-mannitol and Their Application in Henry Reaction

An intermediate of chiral amine with 1,3-dioxane structure(4) was obtained by a four-step reaction of condensation, alcoholysis, azidation and reduction, using D-mannitol as material. Three novel chiral thioureas(6a~6c) were synthesized by the reaction of 4 with 3,5-bis(trifluoromethyl)phenyl isothiocyanate, epiquinine isothiocyanate and quinidine isothiocyanate, respectively. The structures were characterized by ¹H NMR, ¹³C NMR, IR and HR-MS. The catalytic performances and selectivities of 6 were investigated by Henry reaction of nitrocarbol with benzaldehyde. The results showed that the yield and enantioselectivity of (S)-2-nitrophenylethan-1-ol were 69% and 78%, respectively, using Et₃N as base, toluene as solvent, 5 mol% 6b as catalyst at -30 ℃ for 24 h.