Thienylboronic acids, cross-coupling

The synthesis of radioactive ketones with C in carbonyl was achieved by carbonylative cross-coupling of aryl iodides or triflates with methyl-, phenyl-, or 2-thienylboronic acids under elevated pressure of CO. To ensure fast reaction, harsh conditions were used. Interestingly, under such conditions the addition of a base is not necessary (Equation (18))." ... 

Di- and poly-thienyls can be prepared by cross-coupling of 2- and 3-thienylboronic acids in the presence of Pd° catalyst. Another similar method is the cross-coupling of iodothiophenes with stannylthiophenes (Scheme 80). 

By the Suzuki cross-coupling reaction of the substituted thienylboronic acid and 5,6-dibromo-l,10-phenanthroline, Yam and coworkers have developed a series of photochromic 5,6-dithienyl-l,10-phenanthroline ligands, with... 

Tedicyp 66/allylpalladmm(II) chloride dimer (Scheme 29, Table 17) [171, 172]. In contrast, the reaction of 2-thienylboronic acid 68 with aryl halides 69 needs to be performed with 1-5% of the same catalytic system. Alternatively, cross-coupling can utilize arylboronic acids with thiophene halides this yields better results in most cases. 

Arylthiophenes 131 can be prepared by the Suzuki-Miyaura cross-coupling reaction of 2-bromothiophene 107 with different arylboronic acids 130 in the presence of a Tedicyp 66 palladium complex (Scheme 53, Table 31) [171]. The arylation takes place with only 0.1-0.0001 mol% catalyst. The cross-couplings of thienylboronic acids and aryl halides under the same reaction conditions result in slightly poorer yields. 

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