Table 1.
Entry | Catalyst Sequence | L,D-Adduct:L,L-Adduct |
---|---|---|
1 | 4,4-Dimethylaminopyridine (DMAP) | 3:1 |
2 | N-Methylimidazole (NMI) | 4:1 |
3 | Boc-Pmh-OMe | 3:1 |
4 | 5: Boc-Pmh-Asn(trt)-His(tBu)-Asp(OtBu)-Ala-OMe | 1:1.25 |
5 | 4: Boc-Pmh-Hyp(tBu)-Sp5-Tyr(tBu)-Phe-OMe | 3.6:1 |
6 | 10: Boc-D-Pmh-Pro-Aib-Trp(Boc)-Phe-OMe | 13:1 |
7 | 11: Boc-Pmh-D-Pro-Aib-D-Phe-D-Phe-OMe | 1:2.5 |