Halides, alkyl, base induced complexes

There are also a series of more complex eliminations that you should be aware of (Eqs. 10.63-10.67), although we are not going to look at these in any detail. One is the elimination of 1,2-dihaloalkanes and 1,4-dihaloalkanes (the Grob fragmentation) using Zn to create al-kenes or dienes (Eqs. 10.63 and 10.64, respectively). The first step in both reactions involves the oxidative addition of Zn to a C-X bond, a reaction we will cover in detail in Chapter 12. Other eliminations involve y-amino alkyl halides, which can spontaneously undergo elimination (Eq. 10.65), and the base-induced eliminations of both (3-hydroxyketones (Eq. 10.66, the reverse aldol reaction) and 8-ketoketones (Eq. 10.67, the reverse Michael addition). 

Very recently the alkylation of terminal acetylenes by vinyl aryl and heterocyclic halides was induced by Pd complexes under mild conditions. Use of palladium triphenylphosphine, PdCPPha), and a base, such as MeONa in DMF at 50-100 °C, gave high yields of disubstituted acetylenes (e.g. equation 161) . Other catalysts... 

---