<i>o</i>-Halogenation and -Alkoxylation of Phenylglycine Derivatives by Pd-Mediated C-H Functionalization: Scope and Limitations
Orthopalladated derivatives from substituted phenylglycines [Pd(μ-Cl)(C<sub>6</sub>H<sub>3</sub>R<sub>1</sub>C(R<sub>2</sub>)(R<sub>3</sub>)N(R<sub>4</sub>)<sub>2</sub>]<sub>2</sub> (<b>1</b>)...
Saved in:
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-01-01
|
| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/2/236 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| Summary: | Orthopalladated derivatives from substituted phenylglycines [Pd(μ-Cl)(C<sub>6</sub>H<sub>3</sub>R<sub>1</sub>C(R<sub>2</sub>)(R<sub>3</sub>)N(R<sub>4</sub>)<sub>2</sub>]<sub>2</sub> (<b>1</b>) react with halogenating reagents (PhICl<sub>2</sub>, Br<sub>2</sub>, I<sub>2</sub>) (<b>2</b>) to give the corresponding o-halogenated amino acids C<sub>6</sub>H<sub>3</sub>(X)R<sub>1</sub>C(R<sub>2</sub>)(R<sub>3</sub>)N(R<sub>4</sub>)<sub>2</sub> (<b>3</b>). The reaction is general and tolerates a variety of functional groups (R<sub>1</sub> to R<sub>4</sub>) at the aryl ring, the Cα, and the N atom. On the other hand, the reaction of [Pd(μ-Cl)(C<sub>6</sub>H<sub>3</sub>R<sub>1</sub>C(R<sub>2</sub>)(R<sub>3</sub>)N(R<sub>4</sub>)<sub>2</sub>]<sub>2</sub> (<b>1</b>) with PhI(OAc)<sub>2</sub> in the presence of a variety of alcohols R<sub>5</sub>OH (<b>4</b>) gives the o-alkoxylated phenylglycines C<sub>6</sub>H<sub>3</sub>(OR<sub>5</sub>)R<sub>1</sub>C(R<sub>2</sub>)(R<sub>3</sub>)N(R<sub>4</sub>)<sub>2</sub> (<b>5</b>), also as a general process. A partial loss of the enantiomeric excess is observed when the starting phenylglycine is enantiomerically pure, this arising from the formation of bridging azavinylidene (<b>6</b>) and imine intermediate species (<b>7</b>), which were characterized by X-ray diffraction methods. |
|---|---|
| ISSN: | 1420-3049 |