Table 2. ODHB of Homoallylic Alcohols 5 with Me2S·BH3+ TfOHa.
| entry | Stg | R2 | time (h) | yield (%) | 9:10b |
|---|---|---|---|---|---|
| 1 | 5a | CH3 | 10 | 51c | >20:1 |
| 2 | 5b | C2H5 | 10 | 66c | 37:1 |
| 3 | 5c | Z-C2H5 | 5 | 51d | 28:1 |
| 4 | 5d | nC5H11 | 10 | 69 | >20:1 |
| 5 | 5e | cC6H11 | 5 | 80 | 56:1 |
| 6 | 5f | tC4H9 | 5 | 56 | 82:1 |
| 7 | 5g | Ph | 20 | >3 | N/D |
| 8 | 5h | Bn | 10 | 22 | N/D |
| 9 | 5i | CH2Bn | 5 | 59 | >20:1 |
a
Conditions: A 0.2 M solution of 1 (CH2Cl2) at −78 °C was treated with 1 equiv of TfOH, stirred 30 min, 0.2 M of 5 in CH2Cl2 added dropwise, and oxidative workup performed after (time) at −20 °C.
b
NMR assay.
c
Five equivalents of cyclohexene present.
d
Yield after derivatization.(7)