Beside the obtaining of two desired gem-diborylcyclobutane products the syn-and anti-3z, a third linear constitutional isomer product 8a was formed. The formation of this product was envisioned through an unusual 1,5-hydrogen atom transfer (1,5-HAT) scenario as described in Figure . Importantly, the structure of this linear product 8 was confirmed by X-ray crystallographic analysis (please see the X-ray structure of 8a in Figure ). Nevertheless, this structure indicate that the forming of the cyclization reaction initially occurs regioselectively by the addition of the α-diboryl radical of the biradical intermediate (I) to the less steric side of the olefin 2 as proposed pathway of the reaction from I to I-3 on Figure .