Table 1.
| |||
---|---|---|---|
entry | Ni complex | conv (%)b | 1:2:3 (%)b |
1 | Ni(acac)2 | 97 | 68:19:13 |
2 | NiCl2•6H2O | 95 | 45:35:20 |
3 | Ni(cod)2 | >98 | 69:14:17 |
4 | Ni(PPh3)4 | >98 | 55:32:13 |
5 | Ni(PPh3)2Cl2 | >98 | 93:7:<2 |
6 | Ni(dppe)Cl2 | 92 | 3:97:<2 |
7 | Ni(dppp)Cl2 | >98 | <2:>98:<2 |
8 | Ni(dppb)Cl2 | 76 | 8:92:<2 |
9 | Ni(dppf)Cl2 | 75 | 5:95:<2 |
Reactions performed under N2 atm; <2% alkynyl aluminum product observed in all cases.
By analysis of 400 MHz 1H NMR spectra of unpurified mixtures after quench with D2O (0 °C, 30 min); see the Supporting Information for details.