3-(2-Bromovinyl)chlorins: a new approach towards chlorophyll a modification

Regioselective bromination of methyl pyropheophorbide a at the C32-position of the terminal double bond has been carried out as a one-pot two-step addition/elimination process. The elimination occurs with 100% stereoselectivity and bromovinyl 4 has E-configuration of the C3-double bond. The reactivity of unsaturated bromide 4 has been evaluated in the series of the Pd -catalyzed coupling reactions.