Speaker: Chien-An Chen Teacher: Guey-Sheng Liou Direct Arylation Speaker: Chien-An Chen Teacher: Guey-Sheng Liou

Important bi(hetero)aryls

Direct Arylation V.S. Traditional Cross-Coupling Define of direct arylation: Through cleavage of C-H bond Advantage of direct arylation: Without metallic halides by-product →good for enviorment Reduce the synthetic operations →economical

Category of Direct Arylation

Direct Arylation with Organometallic Reagents (Rh-cat.)

Direct Arylation with Organometallic Reagents (Pd-cat.)

Direct Arylation with Organometallic Reagents (Ru-cat.)

Dehydrogenative Arylation

Direct Arylation with (Pseudo)Halides (Pd-cat.)

Direct Arylation on LBG polymer Ullrich Scherf et al. , ACS Macro Lett. 2012, 1, 465−468

Direct Arylation on LBG polymer Takaki Kanbara et al. , ACS Macro Lett. 2012, 1, 67−70

Direct Arylation on LBG polymer Disadvantage: The critical factor of direct arylation polymerization is regioselectivity. Example: Solution method: Use protecting group, methyl, to protect 3-position of thiophene. Example: The two hydrogen atoms are also reactive Cross-linked polymer

Conclusion Until very recently, the majority of catalytic direct arylations have been accomplished with palladium, rhodium, or ruthenium catalysts. However, less-expensive copper, iron, and nickel compounds have been shown. The use of atom-economical terminal oxidants and achieving regioselectivity in intermolecular arylations remain significant challenges.