Several lignin model precursors have been submitted to zinc borohydride reductions and their resultant stereochemistries determined by NMR spectroscopy. Benzoyl carbonyls of α-aryloxy-β-hydroxy systems were reduced without significant stereoselectivity to produce boththreoanderythroisomers. However, protection of the β-hydroxyl with either an acyl, alkyl, or silyl group and subsequent reduction gaveerythzro-specificities of up to 97%. A mechanism where competition for zinc cation complexation between the β-hydroxyl and the α-aryloxy substituent is invoked to explain the observed results. Protection of the β-hydroxyl prevents its complexation with the zinc cation; complexation occurs solely with the α-aryloxy substituent, affording theerythro-isomers.