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
作者:Narshinha P. Argade、Mukulesh Mondal
DOI:10.1055/s-2004-825596
日期:——
Remarkably tuned regioselectivities are obtained in the condensation of 3,5-dihydroxyphthalide (1) with several α,β-unsaturated aldehydes using DBU and neutral conditions. The linear (65-81%) and angular (51-60%) bioactive natural and unnatural benzopyran derivatives are produced exclusively in one step and are described via phenol-keto resonance.