A simple two steps ytterbium triflate-catalysed preparation of 2,2-dimethyl-2<i>h</i>-chromenes from salicylaldehydes and 2-methylpropene
作者:Soizic Prado、Yves L. Janin、Pierre-Etienne Bost
DOI:10.1002/jhet.5570430626
日期:2006.11
The preparation of various 2,2-dimethyl-2H-chromenes was achieved in twosteps via an ytterbiumtriflate-catalysed reaction between salicylaldehydes, trimethylorthoformate and 2-methylpropene. Fromsalicylaldehyde, two reaction products were characterised: 4-methoxy-2,2-dimethylchroman and 2-(1,3-dimethoxy-3-methylbutyl)phenol. The former compound probably results from a Lewis acid-catalysed [2+4]