Heck combined with other cross-coupling processes

4 Heck Combined with Other Cross-coupling Processes 

Heck reaction has also been applied. It is also possible to terminate such a sequence after transmetallation from a zincate [106a,c], either added to the reaction mixture [106a] or generated in situ from an iodoalkene [106cJ. 

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Heck combined with other cross-coupling processes. 121... 

Heck Reactions Combined with Other Cross-Coupling Processes... 

In most of the palladium-catalysed domino processes known so far, the Mizoroki-Heck reaction - the palladium(0)-catalysed reaction of aryl halides or triflates as well as of alkenyl halides or triflates with alkenes or alkynes - has been apphed as the starting transformation accordingly to our classification (Table 8.1). It has been combined with another Mizoroki-Heck reaction [6] or a cross-coupling reaction [7], such as Suzuki, Stille or Sonogashira reactions. In other examples, a Tsuji-Trost reaction [8], a carbonylation, a pericyclic or an aldol reaction has been employed as the second step. On the other hand, cross-couphng reactions have also been used as the first step followed by, for example, a Mizoroki-Heck reaction or Tsuji-Trost reactions, palladation of alkynes or allenes [9], carbonylations [10], aminations [11] or palladium(II)-catalysedWacker-type reactions [12] were employed as the first step. A novel illustrative example of the latter procedure is the efficient enantioselective synthesis of vitamin E [13]. 

In domino transition-metal-catalysed processes, cross-coupling reactions can also be nsed as the starting transformation. Most often, Suzuki, Stille and Sonogashira reactions are employed in this context. They can be combined with a Mizoroki-Heck reaction and other palladium-catalysed transformations. 

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