Stereo- and regio-specificity in organic synthesis promoted by metal ions

Abstract

This paper examines regio-and stereo-specificity for reactions of coordinated organic substrates. The reactions involve addition of coordinated nucleophiles where the specificity arises from non-bonded interactions, substituent effects on the metal, orbital steering directed by the chelates and electronic effects imparted by the geometry required for chelation. The reactions examined include hydration of olefins, addition of nucleophiles at coordinated imines, oxidation and alkylation of coordinated mercaptide ions, stereospecific deuteration for chelated N-benzyl glycine and amine synthesis organised by the metal.

Effect of methylation on the coordination of copper by small azacryptands; the role of geometrically constrained hydrogen bonding in stabilizing terminally coordinated oxygen species

“…Fig. 3 illustrates the comparison with the conformation used in the average-valent dicopper cryptate of the unsubstituted host L 1 .…”

“…The average valence dicopper (1.5) redox state has been shown to occur in the azacryptand series in three situations where the host incorporates a 2-C link between tetraamino caps, i.e. in L 0 and L 4 as well as in L 1 . We wished to discover whether the range of small azacryptand hosts which mimic this unusual biosite could be extended, and, in a first attempt at functionalisation, have synthesised methylated versions of L 1 in order to investigate their complexation properties.…”

Pseudo-Encapsulation: Open Prison Ligands for Metal Ions

“…The direct fusing of the primary amine pendant to the ring has important consequences for complexes of 10 discussed in detail later. 9 10 11…”