Table 1.
| ||||
---|---|---|---|---|
entry | R1 | R2 | additive | S:R |
1 | H | t-butyl | none | 37:63 |
2 | H | t-butyl | L-tartaric acid | 15:85 |
3 | TES | t-butyl | none | 45:55 |
4 | TES | t-butyl | L-tartaric acid | 5:95 |
5 | TES | methyl | L-tartaric acid | 8:92 |
6 | TES | methyl | D-tartaric acid | 94:6 |
7 | TBS | methyl | L-tartaric acid | 5:95 |
8 | TPS | methyl | L-tartaric acid | 5:95 |