Highly Enantioselective Cross-Aldol Reactions of Acetaldehyde Mediated by a Dual Catalytic System Operating under Site Isolation
作者:Xinyuan Fan、Carles Rodríguez-Escrich、Shoulei Wang、Sonia Sayalero、Miquel A. Pericàs
DOI:10.1002/chem.201404215
日期:2014.10.6
Polystyrene‐supported (PS) diarylprolinol catalysts 1 a (Ar=phenyl) and 1 b (Ar=3,5‐bis(trifluoromethyl)phenyl) have been developed. Operating under site‐isolation conditions, PS‐1 a/1 b worked compatibly with PS‐bound sulfonic acid catalyst 2 to promote deoligomerization of paraldehyde and subsequent cross‐aldol reactions of the resulting acetaldehyde in one pot, affording aldol products in high yields with excellent
已开发出聚苯乙烯负载的(PS)二芳基脯氨醇催化剂1a(Ar =苯基)和1b(Ar = 3,5-双(三氟甲基)苯基)。PS- 1 a / 1 b在定点隔离条件下运行,与PS结合的磺酸催化剂2兼容,可促进一锅中对乙醛的解聚和随后生成的乙醛的交叉醛醇缩合反应,从而提供高收率的醛醇产品。优异的对映选择性。研究了水对催化体系性能的影响,并确定了其最佳用量(0.5当量)。双催化体系(1 / 2)允许重复循环再利用(10个循环)。这种方法的潜力通过吩哌啶类似物的两步合成法(总收率68%;ee 98% )和高度对映体富集的1,3-二醇4和3-甲基氨基-1-芳基丙醇5的制备得到证明。合成各种药物结构的关键中间体。