Diruthenium Tetracarboxylate-Catalyzed Enantioselective Cyclopropanation with Aryldiazoacetates
作者:Joshua K. Sailer、Jack C. Sharland、John Bacsa、Caleb F. Harris、John F. Berry、Djamaladdin G. Musaev、Huw M. L. Davies
DOI:10.1021/acs.organomet.3c00268
日期:2023.8.14
nyl)borate], which resulted in the cyclopropanation of a range of substrates in up to 94% ee. Synthesis and evaluation of first-row transition-metal congeners [Cu(II/II) and Co(II/II)] invariably resulted in catalysts that afforded little to no asymmetric induction. Computational studies indicate that the carbene complexes of these dicopper and dicobalt complexes, unlike the dirhodium and diruthenium
制备了一系列手性碗形四羧酸二钌(II,III)催化剂,并在与源自芳基重氮乙酸酯的供体/受体卡宾的不对称环丙烷化反应中进行了评估。二钌催化剂自组装产生C 4对称碗形结构,其方式与二铑催化剂类似。最佳催化剂为Ru 2 ( S -TPPTTL) 4 ·BAr F [ S -TPPTTL = ( S )-2-(1,3-二氧代-4,5,6,7-四苯基异吲哚啉-2-基) -3,3-二甲基丁酸酯,BAr F = 四(3,5-双(三氟甲基)苯基)硼酸酯],这导致一系列底物的环丙烷化反应效率高达 94% ee。第一行过渡金属同系物 [Cu(II/II) 和 Co(II/II)] 的合成和评估总是产生几乎不提供不对称诱导的催化剂。计算研究表明,这些二铜和二钴配合物的卡宾配合物,与二铑和二钌系统不同,容易失去羧酸配体,这会破坏对不对称诱导至关重要的碗形结构。