Boron porphyrins first appeared in the literature during the 1960s and 1970s, in initially available literature the complex was never well characterized. The Boron porphyrin compounds can be synthesized either from the free base porphyrin or from a lithium porphyrin complex as starting material. Two representative examples are shown here. The first is the porphyrin free base reacted with BX in the presence of water.
The second is Li(ttp) reacted with BX. The (BX)(por) can undergo reduction to form a B-B bond and eliminate X, giving (BX)(por). From here, the halides can be replaced with BuLi to give (B-Bu)(por), reacted with alcohols to give (B-OR)(por), or even undergo halogen abstraction via weakly-coordinating anions to give [(B-B)(por)].