基元反应配体的反应.ppt

* A = B为C = C、 R’RC = O、C = N等。 :A – B为一氧化碳:C O、异氰 :C N – R、卡宾:CR2等。 插入反应和消除（反插入）反应 插入反应是指不饱和键插入到M - H键或M - C键中。 特点：金属的氧化态及配位数均没有变化。 Migratory insertion: The term “insertion” is somewhat misleading, in that the process actually proceeds by migration of the adjacent ligand to the metal bound unsaturated species, generating a vacant site. Insertions are usually reversible. If the migrating group has stereochemistry, it is usually retained in both the insertion step and the reverse. 烯烃的插入与? - H消除 1）必须有? - H； 配位 活化 2）M – C 和 C – H 顺式共平面；（如链状烷基金属有机化合物不稳定， 环状金属杂环化合物不容易发生该消除反应） 3）消除生成双键。 Nucleophilic attack on complexed p-unsaturated hydrocarbons is among the most useful of organometallic processes for organic synthesis, since it is exactly the opposite of “normal” reaction chemistry for these substrates. Nucleophilic attack on 18 electron, cationic complexes has been particularly well-studied. Order of reactivity for Kinetically controlled reactions is as follows. Note that Cp is among the least reactive, and as a consequence, is often used as a spectator ligand. 配位烯烃的反应 Wacker 过程 该反应中生成Pd(0)，用Cu(II)氧化再生Pd(II)， 所生成的Cu(I)再被氧气氧化成Cu(II)，从而完成催化循环。 烯烃本来只能接受亲电进攻，但和金属离子配位后，可以接受亲核进攻。该反应形式上与插入反应类似，但是立体化学是不同的。在此反应中，亲核试剂从金属的另一面进攻烯烃，是反式加成。 Cationic iron complexes of alkynes undergo clean nucleophilic attack from the face opposite the metal, to give stable s-vinyl iron complexes. This process has not been used in organic synthesis to any extent. From a synthetic point of view, the most important reaction so far has been the Pd(0) catalyzed reaction of alllylic substrates, a process with overall retention (two inv.) of configuration at carbon. In certain rare cases, attack may occur at the center carbon to form metallacyclobutane. Attack at the central carbon Site Selectivity Attack of h5-dienyl complexes Metal-bound CO is generally reactive towards nucleophiles, providing a major route for the incorporation of carbonyl groups into organic substrates. Neutral metal carb