Coupling of Reformatsky Reagents with Aryl Chlorides Enabled by Ylide‐Functionalized Phosphine Ligands
作者:Zhiyong Hu、Xiao‐Jing Wei、Jens Handelmann、Ann‐Katrin Seitz、Ilja Rodstein、Viktoria H. Gessner、Lukas J. Gooßen
DOI:10.1002/anie.202016048
日期:2021.3.15
organozinc reagents with aryl electrophiles using a cyclohexyl‐YPhos ligand bearing an ortho‐tolyl‐substituent in the backbone. This highly electron‐rich, bulky ligand enables the use of arylchlorides in room temperature couplings of Reformatsky reagents. The reaction scope covers diversely functionalized arylacetic and arylpropionic acid derivatives. Aryl bromides and chlorides can be converted selectively
Iron-Catalyzed Hydromagnesiation: Synthesis and Characterization of Benzylic Grignard Reagent Intermediate and Application in the Synthesis of Ibuprofen
作者:Mark D. Greenhalgh、Adam Kolodziej、Fern Sinclair、Stephen P. Thomas
DOI:10.1021/om500319h
日期:2014.10.27
Iron-catalyzed hydromagnesiation of styrene derivatives using ethylmagnesium bromide has been investigated for the synthesis of benzylic Grignard reagents. The benzylic Grignard reagent formed in the reaction was observed directly and its conformation in solution characterized by multinuclear and variable-temperature NMR spectroscopy. The Grignard reagent could be stored for at least 2 weeks without
已经研究了使用乙基溴化镁对苯乙烯衍生物进行铁催化的加氢脱氢,以合成苄基格氏试剂。直接观察到反应中形成的苄基格氏试剂,并通过多核和可变温度NMR光谱表征其在溶液中的构象。格氏试剂可保存至少2周,而活性不会显着降低。苯乙烯在四氢呋喃中的氢镁化作用产生了单烷基镁和二烷基镁物种,(1-苯乙基)溴化镁(2 ; RMgBr)和双(1-苯乙基)镁(3 ; R 2Mg),而这些物质之间的平衡则有利于二烷基镁物质。烷基交换反应的热力学参数MgBr 2 + R 2的Mg(3)⇌ 2RMgBr(2)进行定量,用焓和形成的熵2从MgBr 2和3为32±7和0.10±0.03千焦计算mol –1分别。该方法以10 mmol的规模被应用为布洛芬合成的关键步骤,该方法通过依次进行铁催化的烷基-芳基和芳基-乙烯基交叉偶联反应,得到4-异丁基苯乙烯,然后加氢放大并与CO反应2个给了布洛芬。在0°C和室温之间的温度下,在大气