Figure 1.'H NMR data, 360 MHz, for 4a and 4c in CDC1,. Differences between the ester inside isomer and the ester outside isomer are readily apparent. by SnC1,/C2H50H. 8 The resulting racemic amine 3 was treated with formaldehyde and HCl to provide, in 42% yield, three diastereomeric Troger's base analogues 4a, 4b, and 4, easily separable by chromatography, and consistently obtained in a 1: 2: 1 ratio (Scheme I).
