Palladium-Catalyzed Ortho-Arylation of O-Phenylcarbamates with Simple Arenes and Sodium Persulfate
Zhao, X; Yeung, CS; Dong, VyM
| HERO ID | 2004346 |
|---|---|
| In Press | No |
| Year | 2010 |
| Title | Palladium-Catalyzed Ortho-Arylation of O-Phenylcarbamates with Simple Arenes and Sodium Persulfate |
| Authors | Zhao, X; Yeung, CS; Dong, VyM |
| Journal | Journal of the American Chemical Society |
| Volume | 132 |
| Issue | 16 |
| Page Numbers | 5837-5844 |
| Abstract | By palladium catalysis, the C-H bond functionalization of O-phenylcarbamates with simple arenes has been achieved using sodium persulfate (Na(2)S(2)O(8)), an inexpensive, easy-to-handle, and environmentally friendly oxidant. This oxidative cross-coupling involves two aromatic C-H bonds undergoing concomitant oxidation to furnish a new biaryl C-C linkage. Excellent reaction efficiencies and regioselectivities were observed with a range of electron-rich, electron-neutral, and electron-deficient arenes; minimal homocoupling of either component was observed. When two reactive C-H bonds are present on the O-phenylcarbamate, selective diarylation can be achieved via quadruple C-H bond functionalization. This work represents a rare example of using O-carbamates as directing groups for catalytic C-H bond activation. Additionally, a palladacycle obtained from an O-phenylcarbamate was prepared and fully characterized. This trifluoroacetate-bridged bimetallic Pd complex exhibits clean conversion to the ortho-arylation product upon treatment with simple arenes. The addition of trifluoroacetic acid (TFA) was found to be critical for successful cyclopalladation of O-phenylcarbamates. We propose this oxidative arene cross-coupling occurs via two discrete C-H bond activations, namely cyclopalladation and electrophilic metalation, within a Pd(0/II) catalytic cycle. |
| Doi | 10.1021/ja100783c |
| Pmid | 20359220 |
| Wosid | WOS:000276991700068 |
| Is Certified Translation | No |
| Dupe Override | No |
| Is Public | Yes |
| Language Text | English |