偶联反应课件

1、偶联反应课件第四部分：导向有机合成的金属有机化学Heck 反应CHR X+PdBaseCR+ Base-HXR = alkenyl, allylic, benzyl, alkynyl, arylX = OTf, Br, I, etc.Sonogashira 反应R X+cat. PdCl2(PP3)2BaseHRcat. CuIRR请同学写催化机理请同学写催化机理偶联反应课件Heck 反应Pd(0)R-XR-PdII-XRHPdII-XRRHRRH-PdII-XNEt3baseRR+ base-HXPdII-XRHRRHR-PdII-XPd (0) or Pd (II)precatalystP

2、dIIRX偶联反应课件Sonogashira 反应R XPdCl2(PP3)2HRRRCuI, Et2NHEt2NH2Cl(Ph3P)2PdRRRR(PPh3)2Pd(0)(Ph3P)2PdRXHRCuI, Et2NHEt2NH2X(Ph3P)2PdRR偶联反应课件分子内Heck 反应从分子间反应到分子内反应或从分子内反应到分子间反应分子间反应：选择性问题分子内反应：构筑环状化合物XPd(0)PdX*优先生成较小的环，五元环六元环，六元环七元环PdXPdXexoendo -H elimination各种因素影响到该反应，要具体问题具体分析。XPd(0)PdXPdX偶联反应课件导向有机合成的金属

3、有机化学 之三交叉偶联反应Cross-Coupling ReactionsR X + M Rcat. MRRRMgXRBX2RSnMe3RZnXNi (0)Pd (0)sp2C-XspC-Xsp3C-Xadditives偶联反应课件导向有机合成的金属有机化学 之三交叉偶联反应Cross-Coupling ReactionsTransition metal-catalyzed cross-coupling reactions between R-X and anorganometallic nucleophile leading to C-C bond formation has been sh

4、own to be particularly useful in organic synthesis. This kind of transformationinvolves a series of fundamental processes at the transition metal centers.In general, most of the cross-coupling reactions require a good leavinggroup which is directly attached at or immediately adjacent to a carbonatom

5、 with sp2 (allylic or benzylic) or sp (propargylic hybridization.Presumably, coordination at these unsaturated centers may facilitate thecleavage of the corresponding C-X bond.As to the unstabilized alkyl complexes, due to their kinetic instability,formation of side products occasionally becomes the major in thecross-coupling reactions of such aliphatic substrates. Several approacheshave been employed to solve this problem.偶联反应课件偶联反应课件Kumada偶联反应偶联反应课件偶联反应课件偶联反应课件Suzuki 偶联反应偶联反应课件偶联反应课件偶联反应课件Stille 偶联反应偶联反应课件偶联反应课件Negishi 偶联反应R X + M Rcat. MRRRZnXPd (0)sp2C-XspC-Xsp3C-Xadditi