Palladium-catalyzed, ligand-free S N 2’ substitution reactions of organoaluminum with propargyl acetates for the synthesis of multi-substituted allenes
作者:Xuebei Shao、Chang Wen、Gang Zhang、Kangping Cao、Ling Wu、Qinghan Li
DOI:10.1016/j.jorganchem.2018.06.020
日期:2018.9
We describe a convenient method for the synthesis of multi-substituted allenes from SN2′ substitution reactions organoaluminum with propargyl acetates: The SN2′ substitution reaction of organoaluminum (0.4 mmol) with propargyl acetates (0.5 mmol) mediated by PdCl2(dppf) (1 mol%) at 60 °C in THF without ligand could produce multi-substituted allenes in moderate to good yields (up to 98%) and high selectivities
Highly Efficient Synthesis of Allenes from Trimethylaluminum Reagent and Propargyl Acetates Mediated by a Palladium Catalyst
作者:Qing-Han Li、Jung-Yuan Jeng、Han-Mou Gau
DOI:10.1002/ejoc.201403008
日期:2014.12
A series of propargylacetates were prepared and used as propargyl electrophiles for coupling reactions with trimethylaluminum. The simple catalytic system of palladium(II) acetate (1 mol-%) and tri(o-tolyl)phosphine (2 mol-%) worked efficiently for a wide variety of aromatic and aliphatic propargylacetates, producing the substituted allenes in good to excellent yields of up to 94 % in tetrahydrofuran
制备了一系列乙酸炔丙酯并将其用作炔丙基亲电试剂与三甲基铝进行偶联反应。乙酸钯 (II) (1 mol-%) 和三(邻甲苯基)膦(2 mol-%)的简单催化体系对多种芳香族和脂肪族乙酸炔丙酯有效地工作,产生了良好的取代丙二烯在四氢呋喃中的产率高达 94%。该过程简单易行,为合成取代的丙二烯衍生物提供了一种有效的方法。根据实验结果,提出了一种可能的催化循环。
Coupling of N-Tosylhydrazones with Terminal Alkynes Catalyzed by Copper(I): Synthesis of Trisubstituted Allenes
作者:Qing Xiao、Ying Xia、Huan Li、Yan Zhang、Jianbo Wang
DOI:10.1002/anie.201005741
日期:2011.2.1
The easy way to allenes: An operationally simple reaction under mild conditions has led to the direct formation of trisubstituted allenes (see scheme; Ts=4‐toluenesulfonyl). An unprecedented copper–carbene migratory insertion process seems to take place, in contrast to classic copper(I)‐catalyzed reactions of diazo compounds.