Table 1.
| ||||
---|---|---|---|---|
Entry | Substrate | Diazo | Product | Yield[a] [%] |
1 | 4 | 49[b] | ||
2 | 2 | 79[b] | ||
3 | 2 | 61[b] | ||
4 | 2 | 69[b] | ||
5 | 2 | 33[c] | ||
6 | 5 | 84[d] | ||
7 | 2 | 51[c,e] | ||
8 | 5 | 98[d] | ||
9[f] | 2 | 56 | ||
10[f] | 2 | 53[b] |
Isolated yield.
d.r. > 20:1.
R4=Me.
R4=t-Bu.
Yield refers to the isolated alkynoate product which was separated from the cyclopropanated byproduct by column chromatography.
Reaction was run at reflux.