= Solution
Only the low-coupling pair remains, so the detected product is the \b[trans <diastereomer>], with approximate coupling 4 Hz. The reaction is highly diastereoselective within the spectrum's detection limit. Its possible absolute configurations are $(2R,3R)$ and $(2S,3S)$.
A conventional <proton> NMR spectrum in an achiral environment cannot distinguish those <enantiomers>: they have the same shifts and couplings. Thus a chiral catalyst plus one set of resonances does \b[not establish an <enantiomeric excess> or an <absolute configuration>]. <Chiral chromatography>, an appropriate chiral NMR method, or a calibrated stereochemical comparison would be needed.
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