Transition metal catalyzed cross-coupling reactions are one of the most important tools available to synthetic chemists for the construction of substituted aroms. An atom and step economical approach is to make direct use of C-H bonds as latent functional groups. These can be activated through chelation assisted transition metal insertion to form cyclometallated intermediates and then functionalized catalytically. Achieving site selectivity in arom. C-H functionalization reactions still remains a major challenge. A common approach is to utilize cyclometallated intermediates to facilitate the formation of ortho-substituted products via oxidative addn. of new coupling partners. Examples of direct meta C-H functionalization however are considerably fewer. One approach to access these products is to exploit similar cyclometallated intermediates to activate remote C-H bonds for SEAr type reactivity. Following our successful meta-selective C-H bond sulfonation of 2-phenylpyridine, our efforts have been focused on expanding the scope of this interesting reactivity. Through an in-depth mechanistic study exploring the nature of the organometallic species involved, we are beginning to identify the key components that favor meta selective SEAr type reactivity over ortho-selective oxidative addn. pathways. This work is informing us for our development of new meta-selective C-H functionalization reactions and our goal of generating new selective catalysts.
|Publication status||Published - 2014|
|Event||248th ACS National Meeting & Exposition - USA, San Francisco, UK United Kingdom|
Duration: 10 Aug 2014 → 14 Aug 2014
|Conference||248th ACS National Meeting & Exposition|
|Country||UK United Kingdom|
|Period||10/08/14 → 14/08/14|