Resolution enolate ions

Resolution (enantiomers), 307-309 Resonance, 43-47 acetate ion and, 43 acetone anion and. 45 acyl cations and, 558 allylic carbocations and, 488-489 allylic radical and, 341 arylamines and, 924 benzene and, 44. 521 benzylic carbocation and, 377 benzylic radical and, 578 carbonate ion and. 47 carboxylate ions and, 756-757 enolate ions and, 850 naphthalene and, 532 pentadienyl radical and. 48 phenoxide ions and, 605-606 Resonance effect, 562 Resonance forms, 43... 

While the chloroborane transfers a hydride ion to an electrophilic carbon atom, M-iso-propyl ephedrine in reaction B selectively transfers a proton to one of the two faces of a nucleophilic enolate [23]. Co-ordination of the nitrogen of the chiral proton source to the enolate counterion is believed to direct the protonation. As the precursor of the enolate is racemic, this reaction is also called deracemization . Obviously, this offers a clear advantage over a classic resolution procedure, as it can be used to convert the whole racemic mixture into the desired enantiomer. 

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