Examination of the Table shows that the reactions occur in consistently good yield to provide the oxime ethers 2d as a mixture of the syn and anti isomers. Under virtually identical experimental conditions the cyclohexyl enamines 1b (R = cyclohexyl; R 1 = R 2 = R 3 = R 4 = H; R 5 = SO 2 Tol or R 1 = R 2 = R 3 = R 4 = H; R 5 = CO 2 Me) showed no tendency to undergo the aza-Cope reaction, underlining the importance of the silyloxy group in promoting the rearrangement.
