Synthesis of Flavans :One-Pot Synthesis of Flavans From 4-Methylcoumarins
作者:Vijayendra P. Kamat、Ratnakar N. Asolkar、Janardan K. Kirtany
DOI:10.1080/00397919808004523
日期:1998.12
Abstract 4-Methylcoumarins (2), obtained by condensation of suitable phenols (1) with ethyl acetoacetate in the presence of sulfuric acid, lead directly to flavans (3) when refluxed with sodium hydroxide and ethanediol.
smoothly from readily available and inexpensive starting materials by using a Ga(OTf)3-catalyzed room temperature hetero Diels–Alder dimerization of salicyl alcohol derivative and a regioselectivephenolmonobromination as the key steps.