Table 2.
Stille Coupling of Vinyl Stannane 5 and Vinyl Iodide 44
 | ||||
|---|---|---|---|---|
| entry | vinyl stannane | reagents and conditions | % yield | (E,E):(E,Z) |
| 1 | 5a | PdCl2(MeCN)2, DMF, rt → 45 °C | trace | nda |
| 2b | 5b | Pd2(dba)3, (2-furyl)3P, CuI, DMSO/THF, rt | 57 | ca. 3.5:1 |
| 3b | 5b | Pd2(dba)3, Ph3As, CuI, DMSO/THF, rt | 54 | ca. 5:1 |
| 4b | 5b | Pd2(dba)3, (2-furyl)3P, CuI, DMSO/THF, 60 °C | 48 | 1:1 |
| 5b | 5b | Pd2(dba)3, Ph3As, CuI, DMSO/THF, 60 °C | 66 | 1:1 |
| 6b | 5b | Pd2(dba)3, Ph3As, CuTC, DMSO/THF, rt | 84 | ca. 10:1 |
| 7c | 5a | Pd2(dba)3, Ph3As, CuI, DMSO/THF, rt | 40 | 1:0 |
| 8c | 5a | Pd2(dba)3, Ph3As, CuTC, DMSO/THF, rt | 69 | 1:0 |
a
nd = not determined.
b
Isolated as a mixture of (E,E)- and (E,Z)-isomers. Ratio was estimated by 1H NMR (600 MHz).
c
Isolated as an inseparable mixture of 45a and homocoupling product 47. Yield was estimated based on 1H NMR analysis (600 MHz) of a purified mixture of 45a and 47.
