The synthesis of alkynylated cyclobutadiene complexes (iron/cobalt) an
d cymantrenes by a metalation/iodination/coupling sequence (MIG-sequen
ce) is reviewed. The MIG-sequence can be applied repeatedly upon C4H4F
e(CO)(3) Or C5H5Mn(CO)(3) leading to multiply ethynylated pi-complexes
. These multiply ethynylated pi-complexes can be envisioned as segment
s out of carbon nets such as 21 or organometallic fullerenynes 39.