Table 1.
Effect of reaction parameters
 | ||||
|---|---|---|---|---|
| Entry | Variation from “standard conditions” | Yielda [%] | drb | eec [%] |
| 1 | None | >95 | 20:1 | 94 |
| 2 | Without CrCl2 | <2 | – | – |
| 3 | Without 4-CzIPN | <2 | – | – |
| 4 | Without blue LED | <2 | – | – |
| 5 | L2, instead of (S,R)-L1 | >95 | 20:1 | 92 |
| 6 | L3, instead of (S,R)-L1 | 84 | 3.1:1 | 47 |
| 7 | L4, instead of (S,R)-L1 | 68 | 1.6:1 | 19 |
| 8 | L5, instead of (S,R)-L1 | 52 | 5.5:1 | 34 |
| 9d | L6, instead of (S,R)-L1 | 71 | 1.8:1 | 46 |
| 10 | L7, instead of (S,R)-L1 | 79 | 2.8:1 | 93 |
| 11 | DME, instead of THF | 72 | 10:1 | 94 |
| 12 | MeCN, instead of THF | 85 | 20:1 | 95 |
| 13 | EtOAc, instead of THF | >95 | 20:1 | 94 |
| 14 | [Ir(dF(CF3)ppy)2(dtbpy)]PF6 instead of 4-CzIPN | >95 | 11:1 | 88 |
| 15 | 5 mol% CrCl2, 6 mol% (S,R)-L1 | 74 | 20:1 | 94 |
| 16 | 0.1 M, instead of 0.05 M, in THF | >95 | 12:1 | 93 |
| 17 | 1.2, instead of 1.5, equiv 1 and 2 | 80 | 20:1 | 94 |
| 18 | 1.2, instead of 1.5, equiv 1 | 90 | 18:1 | 93 |
| 19 | 1.0 equiv H2O was added | <2 | – | – |
| 20 | 1 mL air (added via syringe) | 55 | 14:1 | 87 |
 | ||||
aYields were determined via 1H NMR analysis with 1,3,5-trimethoxybenzene as the internal standard.
bDrs were determined via 1H NMR analysis of the crude product.
cEe was determined via HPLC analysis.
dHomopropargylic alcohol by-product was observed in 1:3 ratio vs the allenol 3.