Table 1. Diels–Alder Reactions of Diene 1 with Dienophiles 2.

| entrya | LA | solvent | temp (°C) | yield (%)b |
|---|---|---|---|---|
| 1 | none | benzene | 80 | nr |
| 2 | Me2AlCl | CH2Cl2 | 25 | ta |
| 3 | MeAlCl2 | CH2Cl2 | 25 | 77 |
| 4 | AlCl3 | CH2Cl2 | 25 | 60 |
The reactions were conducted under 0.2 M concentration of 1.
Purification yield after column chromatography on SiO2. nr = no reaction; ta = trace amount.