Assembling Complex Structures through Cascade and Cycloaddition Processes via Non-Acceptor Gold or Rhodium Carbenes

The ability of highly energetic metal-carbene intermediates to engage in complex cascade or formal-cycloaddition processes is one of the most powerful tools for building intricate molecular architectures in a straightforward manner. Among this type of organometallic intermediates, non-acceptor metal carbenes are particularly challenging to access and, therefore, have experienced a slower development. In this regard, our group has exploited the use of electrophilic gold(I) complexes to selectively activate certain classes of substrates and generate this type of intermediates. Thus, very different type of molecules, such as enynes or 7-substituted cyclohepatrienes, lead to the formation of carbenes under gold(I) catalysis. Related rhodium(II) carbenes can also be generated from cyclohepatrienes. In this account, we aim to summarize our efforts towards the in-situ generation of these highly versatile organometallic species, and the study of their reactivity through formal cycloadditions or complex cascade reactions.