Science of Synthesis

Black, D. A.; Fagnou, K., Science of Synthesis, (2010) 45, 617.

Several illustrations of aryl–aryl coupling reactions are shown in ‌Scheme 67‌ utilizing substrates that do not bear a directing group. For example, arylation of pentafluorobenzene occurs when it is treated with 1-bromo-3-chlorobenzene in contact with a palladium/phosphine catalyst to afford the biaryl ‌185‌; in related chemistry other aryl iodides, bromides, and chlorides can be similarly used.[‌269‌,‌270‌] A rhodium catalyst ‌186‌ is used to mediate the coupling reaction between 1,3-dimethoxybenzene and 1-iodo-4-nitrobenzene to give the biaryl ‌187‌.[‌271‌] Direct arylation of simple benzene has been performed through iridium and palladium catalysis, using aryl iodides and bromides, respectively.[‌272‌,‌271‌] Aryl activation has been previously observed in the borylation of arenes using iridium catalysts, presumably via a similar mechanism.[‌272‌] In much the same way, a reaction between benzene and 1-bromo-2-methyl-4-nitrobenzene is promoted by a palladium catalyst to give 2-methyl-4-nitrobiphenyl (‌188‌); in this case the palladium catalyst is used in contact with solid potassium carbonate and a small amount of pivalic acid. The last compound is considered to be a cocatalyst facilitating C—H cleavage and acting as a proton “shuttle” (from the benzene substrate to the insoluble base).[‌273‌]

‌Meeeee 88‌ Meeeee Meeeeeeee eeeeeee e Meeeeeeee Meeee[‌888‌–‌888‌,‌888‌]

Meeeeeeeeeee Meeeeeeee

8′-Meeeee-8,8,8,8,8-eeeeeeeeeeeeeeeeeee (‌888‌); Meeeeee Meeeeeeee:[‌888‌]

MMMMMMM: Meeeeeeee eeeeeee eee ee eeeeee eeeeeee eee eeeeeeeeeee eeeeeeeee. Meeeeeee eeeeeeeeee ee eeeeeeeee, eeeeeeeeee eeee eee eeeeee ee eeeeee ee eee eee ee eee eeeeeeeee.

M8MM8 (8.8 eeeee), e-Me8MeM•MMM8 (8.88 eeeee), eee Me(MMe)8 (8.88 eeeee) eeee eeeeeee ee eee eeee eee eee eeeeee ee e Meeeeee eeee (88 eM) ee e eeeee-eeeeee eeee (8 eM) eeeeeeee eeee e eeeeeeee eeeeeee eee. Mee eeeeee eee eeeeeeeee eee eeeeeeeeee eeee eeeee (8 ×). 8-Meeee-8-eeeeeeeeeeeee (8 eeeee), 8,8,8,8,8-eeeeeeeeeeeeeeeeee (8.8 eeeee), eee MMM (e eeeeee eeeee ee eee eeeeee ee eeeee eeee eeeeeeee) eeee eeee eeeee eee e eeeeeee, eee eee eeeeeee eee eeeeee ee 888°M eee ee. 88 e. Meee eee eeeeeeee eee eeee, eee eeeeeee eee eeeeee ee ee eee eee eeeee eeeeeeee eee eeeeeeee ee eeeeeee eee eeeee eeeeeee eeeeeeee eeee e eeeeeeeeeeeeee eeeeee (eeeeee eee, eeeeeee); eeeee: 88%.

8-Meeeee-8-eeeeeeeeeeeee (‌888‌); Meeeeee Meeeeeeee:[‌888‌]

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M8MM8 (8.8 eeeee) eee eeeeeee ee eee eee eeeeee ee e Meeeeee eeee (88 eM) ee e eeeee-eeeeee eeee (8 eM) eeeeeeee eeee e eeeeeeee eeeeeee eee. Mee eeeeeeee eeeeee eee eeeeeeeee eee eeeeeeeeee eeee eeeee (8 ×), eeeeee 8.8 M 8-eeeee-8-eeeeee-8-eeeeeeeeeeee (8 eeeee) ee eeeeeee (MMMMMMM: eeeeeeeeee) eee eeeee, eeeeeeee ee Me(MMe)8 (8 eee%), MeeeMeee (8 eee%), eee eeeeeee eeee (8.8 eeeee) ee e eeee ee MMM (8.88 × eee eeeeee ee eeeeeee eeee). Mee eeeeeee eee eeeeee ee 888°M eee ee. 88 e eee, eeee eee eeeeeeee eee eeee, eee eeeeeee eee eeeeee ee ee, eee eee eeeeeeee eeee eeeeeee ee eeeeeeeeeeee ee eeeee e eeeeeee, eeeee eee eeeeeeee ee eeeee eeeeeeeeeeeeee (eeeeee eee, eeeeeee/Me8M); eeeee: 88%.

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) 8/8e, 888.
• 8.Meeeee-Meee, (8888) 8/8e, 888.
• 8.Meeeee-Meee, (8888) 88/8e, 888.
• 8.Meeeee-Meee, (8888) 88/8e, 888.