Further investigations into the mechanism of the o-directed free radical hydrostannation of alkyl and aryl acetylenes

This project demonstrates the extensive further investigations that have been conducted into the O-directed free radical hydrostannation that were required to lay to rest the debate regarding the exact mechanistic path by which this reaction was occurring due to multiple contradicting mechanisms having been published in recent years. This was carried out primarily by the use of a probe previously investigated in 2005 as well as new small molecule probe that provides conclusive evidence to the mechanistic pathway this reaction follows. <br><br>A completely new effect that has been documented here is the role of temperature on the degree of O-coordination in this reaction and how fine tuning of this can completely alter the outcomes from that typically observed at room temperature whether it is at higher or lower temperatures. <br><br>This work also proceeds to build further on the application and use of this reaction in the total synthesis of complex molecules as a method to install tri-substituted olefins by examining its deployment in the presence of a wide range of protecting groups and demonstrates their compatibility as well as their ability to affect the regioisomer outcome of this reaction. <br><br>Further to the experimental evidence we have also demonstrated the use of this new probe to allow for the determination of the relative rate constants involved in this reaction to show the different reactivities of the two common reagents used for this transformation.<br><br><br>