Synthesis and Characterisation of Bridged Morpholine Derivatives Fused to a Phenanthrene Ring System

Abstract

The synthesis of conformationally restricted and facially biased bridged morpholine derivatives fused to a phenanthrene ring system was prepared in a three-step sequence involving: (i) Voight rearrangement; (ii) stereoselective reduction of ketone and (iii) iodine mediated cyclisation, the α-allyl-α-hydroxy-ketones gave the corresponding bridged N-substituted morpholines. One of the bridged morpholine derivatives fused to a phenanthrene ring system was optically active. The NMR spectral analysis and theoretical studies show that substitution on nitrogen prefers exo-orientation, possibly to avoid steric interactions with the phenanthrene moiety.