Table 1.
Intramolecular Diels-Alder Reactions
 | ||||||
|---|---|---|---|---|---|---|
| Temp | A | B | C | D | E | |
| 12a | 170 °C | 0.8 : 1.0 : 0.8 | 78% | 24% | 2.3 : 1.0 | 0.8 : 1.0 |
| 13a-i | 160 °C | 1.4 : 1.0 : 0.3 | >90% | NA | 8.0 : 1.0 | 1.4 : 1.0 |
| 13a-ii | 160 °C | 1.6 : 1.0 : 0.4 | 73% | 37% | 6.5 : 1.0 | 1.6 : 1.0 |
| 13a-iii | 160 °C | 5.2 : 1.0 : 1.2 : 2.0 | 88% | 51% | 1.9 : 1.0 | 5.2 : 1.0 |
| 13a-iv | 160 °C | 3.6 : 1.0 : 1.5 | 50% | NA | 3.1 : 1.0 | 3.6 : 1.0 |
| 13a-v | 160 °C | 1.9 : 1.0 : 1.1 : 0.3 | 93% | NA | 2.1 : 1.0 | 1.9 : 1.0 |
| 13a-vi | 160 °C | 1.3 : 1.0 : 0.6 | 97% | 41% | 3.8 : 1.0 | 1.3 : 1.0 |
| 13a-vii | 160 °C | 1.0 : 1.0 : 1.0 | >90% | NA | 2.0 : 1.0 | 1.0 : 1.0 |
| 13a-viii | 160 °C | 1.0 : 1.0 : 1.0 | >90% | NA | 2.0 : 1.0 | 1.0 : 1.0 |
 | ||||||
|---|---|---|---|---|---|---|
| Temp | A | B | C | D | E | |
| 12b | 185 °C | 1.1 : 1.0 : 0.8 | 52% | 20% | 2.6 : 1.0 | 1.1 : 1.0 |
| 13b-i | 160 °C | 3.6 : 1.0 : 1.0 | 48% | 30% | 4.6 : 1.0 | 3.6 : 1.0 |
| 13b-ii | 160 °C | 1.0 : 1.1 : 3.1 | >90% | 20% | 0.7 : 1.0 | 0.9 : 1.0 |
| 13b-iii | 160 ° | 2.4 : 1.3 : 1.0 | 80% | 36% | 3.7 : 1.0 | 1.8 : 1.0 |
| ” | 130 °C | 3.5 : 2.1 : 1.0 | NA | NA | 5.6 : 1.0 | 1.7 : 1.0 |
| 13b-iv | 160 °C | 1.4 : 1.5 : 1.0 | 76% | NA | 2.9 : 1.0 | 0.9 : 1.0 |
A: product ratio (exo-desired:exo-undesired:endo-1:endo-2). B: combined yield. C: isolated yield of desired exo product. D: exo/endo ratio. E: exo-facial selectivity (desired:undesired).