A novel approach toward “locked” chlorins with increased stability has been studied in detail. The chlorin skeleton is assembled in a convergent fashion from two fragments via a porphyrin forming reaction, followed by 1, 3-dipolar cycloaddition of azomethine ylides, which are formed in situ. Central to the success of the process is the presence of two electron-withdrawing groups in vicinal positions at the perimeter of the porphyrin. As a ...
