Table 3. Scope of Dienes for Selective 1,2- or 1,4-Dicarboxylation^a.

^aReaction conditions: 1 (0.2 mmol) and (nBu₄N)₂C₂O₄ (2.0 equiv) were irradiated with 450 nm LEDs in DMF (0.13 M) at r.t. for 12–48 h under N₂ atmosphere.

^b50 °C was used instead of r.t.