几种钯催化剂的合成

A mixture of palladium dichloride (17.72 g., 0.10 mole), triphenylphosphine (131 g, 0.50 mole), and 1200 ml of dimethyl sulfoxideis placed in a single-necked, 2L,round-bottomed flask equipped with a magnetic stirring bar and a dual-outlet adapter.  A rubber septum and a vacuum-nitrogen systemare connected to the outlets, The system is then placed under nitrogen withprovision made for pressure relief through a mercury bubbler.  The yellow mixture is heated by means of anoil bath with stirring until complete solution occurs (ca. 140℃).  The bath is then taken away, and the solutionis rapidly stirred for approximately 15 minutes.  Hydrazine hydrate (20 g, 0.40 mole) is then rapidly added overapproximately 1 minute from a hypodermic syringe.   A vigorous reaction takes place with evolutionof nitrogen.  The dark solution is thenimmediately cooled with a water bath; crystallization begins to occur at ca. 125℃.  At this point the mixture is allowed to coolwithout external cooling.  After themixture has reached room temperature it is filtered under nitrogen on a coarse,sintered-glass funnel.  The solid iswashed successively with two 50 ml. portions of ethanol and two 50 ml portionsof ether.  The product is dried bypassing a slow stream of nitrogen through the funnel overnight.  The resulting yellow crystalline productweighs 103.5-108.5 g.(90-94% yield).

A meltingpoint determination on a sample in a sealed capillary tube under nitrogen gavea decomposition point of 116℃(uncorrected).  This compares with asimilar determination (115℃)performed on the product prepared by the method of Malatesta and Angoletta.

Properties:

The Pd(PPh3)4 complex obtained by thisprocedure is a yellow, crystalline material possessing moderate solubilities inbenzene (50 g/L), methylenechloride, and chloroform.  The compoundis less soluble in acetone, tetrahydrofuran and acetonitrile.  Saturated hydrocarbon solvents give noevidence of solution.  Although thecomplex may be handled in air, it is best stored under nitrogen to ensure itspurity.

将PdCl₂ (50 g, 0.284 mol)和PPh₃ (162.5 g, 0.62 mol) 加入苯腈（150 mL）中，氮气置换三次，升温到200℃，反应30 分钟，降温至室温析出晶体，滤出固体，用乙 醚洗涤，抽干，得到产品（362 g, 95.8 %）。

Toabsolute acetonitrile (1950 mL) degassed via three vacuum/nitrogen ingresscycle was added dichloropalladium (13 g,73 mmol), the mixture was refluxed at 90~100 °C overnight. The reactant was concentrated toobtain Pd(CH₃CN)₂Cl₂ as orange solid.  To a suspension of Pd(CH₃CN)₂Cl₂(19 g, 73 mmol) in benzene (680mL) was added a solution of dppf (40.6 g,73 mmol) in benzene (680 mL), the mixture was stirred at rt overnight, thereddish brown precipitate formed was collected by filtration, washed withbenzene, and dried in vacuo to give Pd(dppf)₂Cl₂ (~48 g) in over 90% yield.  This is pure enough for the next step, thecomplex can be recrystallized from chloroform/benzene.