摘要:
Irradiation of 10-alkyl-10-carbomethoxy-β-ionones 1a, b under basic conditions gave 2-oxatricyclo[4,4,0,01.5]-decane derivatives 5a, b; the mechanism involves initial cis–trans isomerization of the C7–C8 double bonds followed by [2+4] cycloaddition reaction and double bonds isomerization.