First total synthesis of ( )-sepicanin A

A facile approach for the first total synthesis of naturally occurring geranylated flavanoids sepicanin A has been obtained with total yield 16％ starting from 2,4,6-trihydroxyacetophenone after four steps.The key step was the protic acids (HCl or p-TsOH)-catalyzed benzopyrone formation in a protic polar solvent by deprotection and cyclization of chalcone in one step.