Table 1.
Optimization of visible‐light‐mediated installation of N
ϵ
Ac sidechains; iridium(III) catalyst, (Ir[dF(CF3)ppy]2(dtbpy))PF6, shown.
|
Entry |
Peptide [mM][a] |
N‐allyl acetamide 2 [mM] |
Catalyst [mol %] |
TCEP [mM] |
pH |
Conversion [% 1 to 3 a][b] |
Time to completion[d] |
|---|---|---|---|---|---|---|---|
|
1 |
1 |
500 |
1 |
50 |
7 |
36 |
<2 hours |
|
2 |
0.5 |
250 |
1 |
50 |
7 |
43 |
<2 hours |
|
3 |
0.5 |
250 |
1 |
2.5 |
7 |
42 |
<2 hours |
|
4 |
0.5 |
250 |
1 |
2.5 |
8 |
52 |
<2 hours |
|
5 |
0.5 |
250 |
5 |
2.5 |
8 |
51 |
<1 hour |
|
6 |
0.5 |
100 |
5 |
2.5 |
8 |
55 [51][c] |
45 mins |
|
7 |
0.5 |
100 |
5 |
2.5 |
8 |
47 [54][c] |
2 mins[e] |
|
8 |
0.5 |
100 |
10 |
2.5 |
8 |
49 |
<1 hour |
[a] 6 M Gdn⋅HCl, 0.1 M Na2HPO4, organic component DMSO, MeOH or MeCN. [b] % conversion calculated by analytical HPLC. [c] Isolated yield given in brackets. [d] All reactions conducted under blue LED lights at room temp. (set up 1), except for entry 7. [e] PhotoRedOx Box used for entry 7 (set up 2); 34 mW cm−2 LED bulb, 450 nm.