Dibal-amine complex

In reactions requiring palladium 0), formation of the active complex may be achieved more conveniently by reduction of a palladium(ll) complex, for example, Pd 0Ac)2- Any phdsphine may then be used in the reaction, without the need to synthesize and isolate the corresponding palladium 0)-phosphine complex. Only 2-3 equivalents of phosphine may be needed, making the palladium(O) complex coordinatively unsaturated and therefore very reactive. The reduction of palladium li)to palladium(o) can be achieved with amines, phosphines, alkenes, and organometailics such as DIBAL-H, butyl lithium, or trialkyl aluminium. The mechanisms are worth giving as they illustrate the basic steps of organometallic chemistry. 

Selective reduction of the methyl ester to the corresponding aldehyde using DIBAL at low temperature and subsequent reductive amination with iodopiperonyl-ammonium chloride affords the tricarbonyliron-cyclohexadiene complex with the secondary alkylamine in the side chain. Iron(O)-mediated oxidative cydization... 

---