Mechanistic Considerations and the Role of Additives

Returning to the classical Mizoroki-Heck reaction and regarding the regioselectivity of its intramolecular version, one particularly appreciated feature is the commonly 

As seen before, regioselectivity in the intramolecular Mizoroki-Heck reaction can be controlled or directed by cautious choice of substrates and reaction conditions. In reality, the mechanism of the Mizoroki-Heck reaction is much more complex than the oversimplified 

Besides the different mechanistic pathways mainly depending on the substrate types, the Mizoroki-Heck reaction can also be run under several conditions with diverse additives which affect the outcome. A major achievement in this field was the discovery of the so-called Jeffery conditions [25-28]. Mizoroki-Heck reactions are indeed greatly accelerated by the use of inorganic bases in combination with a phase-transfer agent which allows lowered reaction temperatures. In some cases, Jeffery conditions can even lead to the endo-cyclizod product, whereas standard conditions give the exo-cyclized compound [8]. 

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