Bis(propynyl)zirconocene (6a) reacts with tris(pentafluorophenyl)borane to yield the carbon-carbon coupled Cp 2M(μ-RC 4R)B(C 6F 5) 3 betaine product 4a (M Zr, R CH 3). A variety of differently substituted analogs was prepared (M Zr, R = n-butyl, phenyl, cyclohexyl; M Ti, R CH 3; M Hf; R CH 3, phenyl, SiMe 3). These complexes 4 are chiral due to the presence of a rather stable propeller-like RB(aryl) 3 conformation. The activation barrier of the intramolecular enantiomerization process of many examples of this series of complexes was determined by dynamic 1H NMR spectroscopy, with †G ↕ values ranging from ca. 13 to 16 kcal mol −1, depending on the substitution pattern. Complex 4a reacts with 2,6-dimethylphenylisocyanide to yield the methylenecyclopropene derivative 1 that was characterized by X-ray diffraction.