To probe the metathesis process NacNacZn(thienyl) complex 10 was synthesized and reacted with 0.5 equivalent of (H-BBN)2. While the metathesis did proceed at room temperature to form thienyl-BBN, 3a, only 50% of 10 was consumed to form a single new NacNacZn product that was not compound 1. Instead, the zinc complex displayed NMR data consistent with formation of NacNacZn-(-H)2-BBN, 11 (Figure ). This included a 11 B NMR resonance (at -13.5 ppm)