Regiospecific (biogenetic-type) synthesis of 2-methyl-5H-pyrano[3,2-c][1]benzopyran-4-one, the basic skeleton in citromycetin
Abstract
Regiopspecific cyclization of the acetal (4g), derived in 5 steps from 2′-benzyloxyacetophenone (3a), gave the pyrone (6a), which was easily converted into 2-methyl-5H-pyrano[3,2-c][1]benzopyran-4-one (1b), the basic skeleton in citromycetin (1a).