The Asymmetric Reformatsky Reaction : an NMR Investigation about the Nature of some Organozinc Reaction Species

In order to obtain some information about the nature of the intermediate organometallic species formed during the asymmetric rection between the Reformatsky reagent 1b, and benzaldehyde 1c,in the presence of (1S,2S)-l-phenyl-2- N,N-dimethylamino-3-tbutyl-dimethylsilyloxy-1-propanol, la, a spectroscopic NMR investigation has been carried out directly on the mixtures of 1b, 1c and the chiral ligand 1a. To semplify ternary mixture analysis, binary mixtures containing 1b and 1c or 1b and 1a have been studied. Some hypotheses, about the plausible nature of the intermediates reaction species, which seem to justify the chiral discrimination results so far reached by using the above optically active ligands, are reporled.