Table 3. Comparison of the Catalytic Activity of 8–19 in the Model Hydrosilylation System [Yields and Isomeric Content (α/β Ratio)]a,b.
| entry | catalyst | yield and isomeric ratio at 80 °C/6 h | yield and isomeric ratio at 100 °C/4 h |
|---|---|---|---|
| 1–2 | 8 | 83 (67/33) | 25 (60/40) |
| 3–4 | 9 | 64 (35/65) | 60 (28/72) |
| 5–6 | 10 | 66 (38/62) | 60 (27/73) |
| 7–8 | 11 | <5 | 14 (57/43) |
| 9–10 | 12 | 7 (49/51) | 44 (66/34) |
| 11–12 | 13 | 5 (44/56) | 83 (67/33) |
| 13–14 | 14 | 49 (52/48) | 82 (35/65) |
| 15–16 | 15 | 81 (62/38) | 82 (60/40) |
| 17–18 | 16 | 81 (60/40) | 83 (55/45) |
| 19–20 | 17 | 42 (41/59) | 80 (42/58) |
| 21–22 | 18 | 90 (20/80) | 85 (48/52) |
| 23–24 | 19 | 41 (54/46) | 75 (43/57) |
a
PhC≡CH (5.0 × 10–4 mol, 1 equiv), Et3SiH (5.0 × 10–4 mol, 1 equiv), catalyst 8–19 (5.0 × 10–7 mol); toluene (0.5 mL).
b
Yields of products were determined by 1H NMR spectroscopy using 1,2-dimethoxyethane as the standard, whereas the isomeric content was determined on the basis of the alkene coupling constants.