Squaramide-Linked Chloramphenicol Base Hybrid Catalysts for the Asymmetric Michael Addition of 2,3-Dihydrobenzofuran-2-carboxylates to Nitroolefins
作者:Linjie Yan、Guanxin Huang、Haifeng Wang、Fangjun Xiong、Haihui Peng、Fener Chen
DOI:10.1002/ejoc.201701485
日期:2018.1.10
of hybrid catalysts incorporating chloramphenicol base with another chiral scaffold using a squaramide linker have been developed and successfully applied in Michael addition of 2,3-dihydrobenzofuran-2-carboxylates to nitroolefins. The controlling experiments suggested that the hybrid catalysts were more reactive than non-hybridized bifunctional catalysts and the matching of chiralities between two
已开发出一系列新型混合催化剂,将氯霉素碱与另一种使用方酸酰胺接头的手性支架相结合,并成功应用于 2,3-二氢苯并呋喃-2-羧酸盐与硝基烯烃的迈克尔加成反应。对照实验表明,杂化催化剂比非杂化双功能催化剂更具反应性,两个支架之间手性的匹配对于高反应性和立体选择性至关重要。事实证明,这种混合有机催化剂适用于各种底物。在 0.5 mol% 催化剂负载量的情况下,以高产率(高达 98%)获得了一系列带有季-叔立体中心的 2,3-二氢苯并呋喃-2-羧酸酯衍生物,并具有出色的对映选择性(高达 99% ee)和中等非对映选择性(高达 8/92 dr)。