Cyclic monomer and dimer formation with different catalyst compositionsa.
Entry | Catalyst | Cu(i) | Ascorbic acid | Piperidine (% vol) | Monomer : dimer | % yield |
---|---|---|---|---|---|---|
A | CuI | 1.5 | 5 | 20 | 8.6 : 1 | 87.4 |
B | [Cu4I4(pip)4] | 1.5 | 30 | 0 | 5.04 : 1 | 89.2 |
C | [Cu4I4(pip)4] | 1.5 | 5 | 20 | 7.14 : 1 | 84.3 |
D | CuI | 1.5 | 5 | 0 | 5.90 : 1 | 73.8 |
E | CuI | 1.5 | 30 | 0 | 3.74 : 1 | 74.1 |
F | CuI | 1.5 | 30 | 1 | 4.24 : 1 | 84.1 |
G | CuI | 1.5 | 30 | 3 | 6.04 : 1 | 84.0 |
H | CuI | 1 | 5 | 20 | 9.53 : 1 | 66.8 |
I | CuI | 0.5 | 5 | 20 | 8.04 : 1 | 66.0 |
Cu(i) and ascorbic acid given in equivalents.