DBU-Induced Phenol-Keto Resonance in 3,5-Dihydroxyphthalide: Regioselectivities in Condensations with α,β-Unsaturated Aldehydes - Facile Synthesis of Bioactive Natural and Unnatural Benzopyrans - Mondal, Mukulesh ; Argade, Narshinha P (Synlett, 2004)