Chiral picolylamines for Michael and aldol reactions: probing substrate boundaries
作者:Thomas C. Nugent、Ahtaram Bibi、Abdul Sadiq、Mohammad Shoaib、M. Naveed Umar、Foad N. Tehrani
DOI:10.1039/c2ob26382c
日期:——
organocatalyst template, a vicinal chiral diamine based on a pyridine-primary amine motif. The addition of cyclohexanone to β-nitrostyrene has many catalyst solutions, but cyclopentanone and isobutyraldehyde additions continue to be challenging. PicAm-3 (10 mol%) readily allows the Michael addition of cyclopentanone or isobutyraldehyde (5.0 equiv.) to β-nitrostyrene derivatives. By contrast, PicAm-1 (7.0 mol%)
在这里,我们报告了有关通过吡啶甲基胺有机催化剂模板(基于吡啶-伯胺基序的邻位手性二胺)增加底物宽度的研究。的加法环己酮 到 β-硝基苯乙烯 有很多催化剂溶液,但是 环戊酮异丁醛的添加仍然具有挑战性。PicAm- 3(10 mol%)允许迈克尔添加环戊酮 或者 异丁醛(5.0当量)β-硝基苯乙烯衍生物。相比之下,PicAm- 1(7.0 mol%)最适合催化Aldol反应环己酮 或者 环庚酮(3.3当量)与芳族醛。报告了18种产品,每种反应类型都报告了新产品(4b–d,9c)。通常注意到非常好的产率和立体选择性。需要酸添加剂的反应通过瞬时手性烯胺进行,并提出了双功能催化模型的机理实例。