Table 1. Summary of High-Throughput Ligand Screening for the Vinylation of 23 with Ethylene Gas.
| HPLC (area %) |
|||
|---|---|---|---|
| entry | cat (mol %) | 23 | 19 |
| 1 | PdCl2 (20), (p-Tol)3P (40) | 20.2 | 53.6 |
| 2 | PdCl2 (20), (o-MeOC6H4)3P (40) | 43.6 | 9.2 |
| 3 | Pd(OAc)2 (20), Xantphos (20)a | 12.3 | 70.7 |
| 4 | Pd(dppf)Cl2·CH2Cl2 (10) | 69.6 | 13.8 |
| 5 | PdCl2 (20), DPEphos (20) | 0.9 | 61.1 |
| 6 | Scheme 4, method B | NDb | 94.5 |
The reaction was conducted in DMF (50 v/w) in the absence of PTZ.
ND = not detected.
