Variations on a theme—recent developments on the mechanism of the Heck reaction and their implications for synthesis

The Heck reaction has been used extensively over the past 30 years for the elaboration of alkenes. Although many examples have been published in the literature it is only in the last few years that detailed mechanistic studies have been undertaken and a clearer understanding of the active species has emerged. This review will examine the implications of recent details on the mechanism of the Heck reaction using both traditional and non-traditional catalytic systems, highlight mechanistic details which must be updated in textbooks and summarise the protocols which a practising chemist might use to perform a successful Heck coupling.