Table 2. Optimized Fukuyama–Mitsunobu reaction conditions for N-allylation of amino acid residues on Rink amide Resina.
| |||
|---|---|---|---|
|
| |||
| entry | T/°C | time/h | % conversionb |
| o-nitrobenzenesulfonyl protection | |||
| 1 | 25 | 12 | quantitative |
| 2 | 100c | 0.25 | quantitative |
| Mitsunobu reaction | |||
| 3 | 25 | 6 | 70% |
| 4 | 25 | 12 | 90% |
| 5 | 100c | 0.16 | quantitative |
| o-nitrobenzenesulfonyl deprotection | |||
| 6 | 25 | 2 | quantitative |
| 7 | 50c | 0.08 | quantitative |
a
Optimization studies were performed with peptide 9 sequence; results of N-allylation of alanine are shown.
b
Determined from analytical HPLC areas.
c
With microwave irradiation.