A GENERAL SYNTHETIC METHOD OF 1,2-DIHYDROCYCLOBUTA[<i>c</i>]COUMARIN AND ITS 1-SUBSTITUTED DERIVATIVES

Abstract

Abstract 4-Methoxycoumarin reacts photochemically with ethylene and its substituted derivatives to form 8b-methoxy-1,2,2a,8b-tetrahydrocyclobuta [c]coumarin and its 1-substituted derivatives, which in turn eliminate methanol by boron trifluoride etherate in benzene to give the corresponding 1,2-dihydrocyclobuta[c] coumarins in high overall yields.