1613114-49-0Relevant articles and documents
Aromatic homologation by non-chelate-assisted RhIII-catalyzed c-H functionalization of arenes with alkynes
Pham, Manh V.,Cramer, Nicolai
supporting information, p. 3484 - 3487 (2014/04/03)
Larger condensed arenes are of interest owing to their electro- and photochemical properties. An efficient synthesis is the catalyzed aromatic annulation of a smaller arene with two alkyne molecules. Besides difunctionalized starting materials, directed C-H functionalization can be used for such aromatic homologation. However, thus far the requirement of either pre-functionalized substrates or suitable directing groups were limiting this approach. Herein, we describe a rhodium(III)-catalyzed method allowing the use of completely unbiased arenes and internal alkynes. The reaction works best with copper(II) 2-ethylhexanoate and decabromodiphenyl ether as the oxidant combination. This aromatic annulation tolerates a variety of functional groups and delivers homologated condensed arenes. Aside from simple benzenes, naphthalenes and higher condensed arenes provide access to highly substituted and highly soluble acenes structures having important electronic and photophysical properties. Multi-ring circus: The aromatic homologation of unfunctionalized, directing-group-free arenes with internal alkynes is promoted by a rhodium(III) catalyst in conjugation with suitable oxidants. The method tolerates a variety of functional groups and delivers highly substituted and highly soluble condensed arenes. These products provide access to acene structures with important electronic and photophysical properties.
