Borylation of aromatic C-H bonds

Iridium-Catalyzed Silylation and Borylation of Aromatic C—H Bonds... 

As an alternative to the electrophific functionalization of PS, the iridium-catalyzed borylation of aromatic C—H bonds to functionalize PSs with different tacticities (atactic, isotactic, and syndiotactic Fig. 24A) was reported. Because the borylation did not occur at the C—H bonds of sp carbons, it did not affect the tacticity of PSs. Similar to the case of molecular arenes, this C—H borylation of PS was achievable with bis(pinacolato) diboron (B2pin2) or pinacolborane (HBpin) and generated a mixture of meta- and para-substituted borylated PSs. However, the ratio of the two isomers was different than that of isopropylbenzene because a phenyl ring was attached to every other carbon in the PS backbone, the meta C—H bonds of PS were more sterically hindered than the para C—H bonds. Thus, while the ratio of meta- and para-substituted isomers in the C—H borylation of isopropylbenzene was 7 3, the C—H borylation of PS under identical... 

Figure 24 Functionalization of (A) PS and (B) PSD via iridium-catalyzed borylation of aromatic C—H bonds.

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See also in sourсe #XX -- [ ]

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