Concise synthesis of belamcandaquinones A and B by palladium (O) catalyzed cross-coupling reaction of bromoquinone with arylboronic acids

Synthetic approaches to 1-(2-chlorophenyl)isoquinoline-3-carboxylic acid

“…16 Moreover, side reactions and catalyst deactivation took place when additions of arylboronic acid 15 and potassium phosphate were repeated. Analysis of the reaction mixture showed the formation of some volatile 2-chlorophenol 17 (resulting from a concurrent oxidative dehydroboration 22,23 ) and of a small amount of a mixture of unidentified polyaryl compounds. 24 On the other hand, the coupling reaction of compound 15 (using only 3 mol% of tetrakis(triphenylphosphine)palladium) with the brominated derivative 14 led to the ester 16 in 90% isolated yield, if 2 equivalents of arylboronic acid 15 and potassium phosphate were added in two portions over 16 hours.…”

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“…The preparation of mono adducts from DCNQ (2) allows a different group to be introduced in a subsequent Suzuki reaction, thereby enabling the preparation of unsymmetrical 2,3-diaryl naphthoquinones. This process is illustrated by the preparation of the unsymmetrical diaryl naphthoquinone (10) from DCNQ (2) in two steps, via the monoaryl naphthoquinone (9).…”

“…[7] However, this technique has received limited attention for the arylation of haloquinones, with only a handful of bromoquinones having been tried [4,8,9] and not always successfully. [10] This appears to be due, at least in part, to the poor stability of bromoquinones, particularly under the aqueous conditions usually employed in the Suzuki coupling.…”

Facile attachment of functional moieties to crosslinked polystyrene beads via robust linkages: Suzuki reactions using polymer-supported boronic acids

“…(iv) Suzuki reactions tend to be accompanied by hydrolysis of the B-C bonds. [15][16][17][18] In the present case this removes unreacted boronic acid residues 5 from the beads and simply leaves unsubstituted phenyl residues.…”