Scheme 4. Two potential routes to 14via proposed complex 9. Path 1 forms 14via a [2 + 2] cycloaddition of 8 and 9. Path 2 forms 14 through dimerization of 9 then a [2 + 2] cyclisation, followed by 1,3 migration and a single electron transfer, giving 18 and 19. Path 2 also has the potential to form decomposition complex 10via radical cyclisation of 19.