1-Trimethylsilyloxy-1-methoxy-1, 3-dienes (3a-d) regioselectively add to aldonitrones at− 20° C in dichloromethane in the presence of 10–20% of trimethylsilyl triflate to give γ- adducts in high yields; on the other hand, 1-trimethylsilyloxy-1-methoxy-1, 3-hexadiene (3e) displayes a reversed regiochemical preference affording the α-adduct as the major product.