Table 1.
Reaction optimizations.
|
Entry |
Deviation from standard conditions A |
Yield 2 a [%][a] |
|---|---|---|
|
1A |
none |
88 |
|
2A |
DDQ (100 mol %) at +1.30 V[b] |
traces |
|
3A |
CoTPP (2.5 mol %) at +2.00 V |
traces |
|
4A |
MeCN as solvent |
n.d. |
|
5A |
TFE as solvent |
traces |
|
6A |
no current |
n.d. |
|
Entry |
Deviation from standard conditions B |
Yield 2 j [%][a] |
|---|---|---|
|
1B |
standard conditions A |
n.d. |
|
2B |
no mediator at +2.40 V |
45 |
|
3B |
none |
60 |
|
4B |
DDQ (25 mol %) |
47 |
|
5B |
no mediator at +1.30 V |
n.d. |
|
6B |
no current |
n.d. |
|
7B |
CoTPP (2.5 mol %) at +2.00 V |
79 |
All reactions were stirred at rt, overnight and performed on scales of 150 μmol. No reference electrode was used to set the cell voltage. [a] Isolated yields, traces indicate minor conversion detected. [b] Performed in MeCN and HFIP, delivering traces of product 2 a in both reactions only. n.d.=not detected; GC=glassy carbon; DDQ=2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone; CoTPP=cobalt(II) tetraphenylporphyrin; TBA=tetra‐n‐butyl ammonium.