[η5‐CpFe(CO)2]2 undergoes a previously unknown type of reaction with phoshorus ylides Ph3PCHR (RH, Me, iPr) to give the cis‐ and trans‐alkyli‐ene complexes 1 and 2 and a small amount of the organometal‐substituted ylide 3, Surprisingly, analogous manganese complexes react with methylenephosphorane with ortho‐acylation of one of the P‐phenyl groups. (Figure Presented.) Copyright © 1981 by Verlag Chemie, GmbH, Germany