One of the major current challenges of organometallic chemistry is to establish new processes that meet economic needs and environmental welfare. In this context, the use of organozinc reagents has regained significant interest from the chemical community. Inexpensive and barely non-toxic, their use offers the possibility to develop new reactions that are more efficient and selective and thus reduce the number of synthetic steps to achieve a given transformation. Over the last few years, our group has actively developed new synthetic methodologies based on zinc-mediated reactions. More specifically, the carbometallation of unactivated alkenes and alkynes by zinc enolate derivatives including radical zinc atom transfer reactions and the development of new organometallic species of carbenoidic type have been studied. A brief overview of our activity in this field for the period 2007-2009 is described hereafter.
Carbometallation of Unactivated Alkenes and Alkynes by Addition of Zinc Enolates or by Radical Zinc Atom Transfer
The carbometalation reaction of zinc enolates on unactivated double bonds has emerged over the past decade as a mechanistically interesting (apparently contra-thermodynamic) and synthetically useful reaction. Our recent mechanistic studies have shown that in addition to the "classical" polar carbozincations, radical-polar crossover processes can also take place.