Anti-14 was the major product in allylations of imine 12 with allyltrimethylsilane regardless of Lewis acid employed (Table ). AlCl3, SnCl4 and Cu(OTf)2 provided the best yields and diastereomeric ratios of product for the reaction (Table , entries 3, 4 and 9). The anti selectivity observed for most Lewis acids can be rationalized through stereoelectronic considerations of each mode of attack on half-chair conformers 15a and 15b (Figure ). Ruling out the trajectories of attack that lead to twist-boat products, approach of the nucleophile to the six-membered ring chelate is sterically unhindered in the case of lower energy half-chair conformer 15a while sterically hindered on the higher energy conformer 15b. Stereoelectronic interactions of nucleophilic attack and conformational preferences of the chelate are reenforcing in this case and predict for the major anti-13 product observed.