The enzymes tyrosinase and laccase from a crude extract of the button mushroom (Agaricus bisporus) can be employed to catalyze the domino reaction between phenol and various cyclic 1,3-dicarbonyls using atmospheric oxygen as the oxidizing agent and yielding annulated benzofuranes in a highly efficient and sustainable manner.
Laccase-catalyzed domino reactions of 4-hydroxy-6-methyl-2H-pyran-2-one or substituted 4-hydroxy-2H-chromen-2-ones with catechols using molecular oxygen as an oxidant afford coumestans and related O-heterocycles with yields ranging from 51% to 99%.