Transition-Metal-Catalyzed Cyclopropanation of Nonactivated Alkenes in Dibromomethane with Triisobutylaluminum
作者:Gerhard Brunner、Susanne Elmer、Fridtjof Schröder
DOI:10.1002/ejoc.201100528
日期:2011.8
Catalytic amounts of CuI salts, CpTiCl3, and [CpFe(CO)2]2 are similarly effective. 2-Methylpropane, generated after quench of excess TIBA can be trapped, and excess dibromomethane can be recycled, which makes the method industrially applicable. Solvent-free DIBAH or TIBA reduction of unsaturated carbonyl compounds, followed by in situ TIBA cyclopropanation of the unsaturated aluminum alcoholates in
非活化烯烃与廉价三异丁基铝 (TIBA) 的环丙烷化反应,在二溴甲烷作为溶剂和试剂中,在环境温度下由 FeCl3 有效催化。CuI盐、CpTiCl3和[CpFe(CO)2]2的催化量同样有效。可捕集过量TIBA骤冷后产生的2-甲基丙烷,回收过量二溴甲烷,具有工业应用价值。不饱和羰基化合物的无溶剂 DIBAH 或 TIBA 还原,然后不饱和铝醇化物在二溴甲烷中的原位 TIBA 环丙烷化得到环丙基链烷醇。二烯醇,例如香叶醇、芳樟醇或正菘醇在其远端位置被选择性地环丙烷化,这允许合成风味和香味化合物,例如 Δ-柠檬醛、顺式-javanol 和 7-甲基-乔木。