4-fluorophenylboronic acid

Bromobenzaldehyde and 4-fluorophenylboronic acid were coupled in DMF using tetrakis(triphenylphosphine)palladium(0) as catalyst [85] (see a more extended description in [42]). 

OS 45] [R 17] [noprotocol] For the reaction of 3-bromobenzaldehyde and 4-fluorophenylboronic acid, improved conversion was found for a micro reactor, composed... 

Resin 4 (R1 = CH3) (50 mg, 0.014 mmol) was weighed into a conical Personal Chemistry Smith process vial equipped with a conical-shaped stir bar. To the resin was added 4-fluorophenylboronic acid (11 mg, 0.08 mmol), DMF (1 ml), 2 M aqueous sodium carbonate (80 pi), and di-chlorobis(triphenylphosphine)palladium(II) (1-2 mg). The heavy walled glass vial was crimp sealed and placed on the Gilson platform. The micro-wave program was set to a 5 min duration at 180° on the normal absorption setting and the vial was then processed. After completion, the vial was decrimped and resin 5 (R1 — CH3, R2 = 4-F-phenyl) was transferred to a fritted tube and washed with DMF, H20, MeOH, and DCM (3x each). 

Pd PPh3)4. Yields were in the range of 70-90%. No protection of the indole-N was necessary. <94SL93> This procedure was applied to coupling of 6-bromoindole with 4-fluorophenylboronic acid and proceeded in 90% yield. <94JMC4423>... 

A variety of discotics can be prepared from the tetrabromopyrene 59 as shown in Scheme 4.17. Thus, the Suzuki coupling between 59 and commercially available methoxyphenylboronic acid or 1-fluorophenylboronic acid yields tefiaphenyl derivatives 64 and 67, respectively. Demethylation of 64 with HBr yields 1,3,6,8-tetrakis(4-hydroxyphenyl)-pyrene 65 which can be alkylated with different alkyl halides to tetraethers 66. Similarly, esterification of the tetraphenol with acid chloride or benzoic acid affords tetraesters 66 (R = COR) or benzoate 66 (R = CORiR), respectively [111]. Replacement of fluoro atoms with alkylthiolates generates nonmesomorphic tetra-thioethers of pyrene 68. 

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