Vinylic C-H activation. Over the course of 14 days, the room temperature reaction of 1 with styrene (1 equiv.) in C6D6 afforded the vinylic C-H activation product 4a in 78 % NMR yield (Figure ). 4a was isolated in pure form and crystals suitable for X-ray diffraction have been grown confirming the (E)-β-alumination of styrene (Figure ). The new species exhibits a broadened hydride resonance at δH = -15.58 ppm in the 1 H NMR spectrum integrating to 3H and a singlet at δp = 29.0 ppm in the 31 P{ 1 H} NMR spectrum being characteristic for a (PMe3)3Fe-(μ-H)3-Al motif that resulted from the C-H activation reaction. The PhCH=CH protons resonate at δH = 7.86 and δH = 7.34 ppm respectively showing a large coupling constant of 3 JHH = 19.9 Hz diagnostic for an (E)-configuration of the C=C double bond.