The reduction of unactivated esters by SmBr2-NMEA was also examined. Methyl 3-phenylpropanoate as well as γheptalactone, δ-decalactone, and ε-caprolactone were each reduced quantitatively by a slight excess of SmBr2-NMEA to the respective alcohol and diol products shown in Scheme 4. While the reductions of unactivated esters by SmI2-wateramine and 6-membered lactones by SmI2-water are known, 5and 7-membered lactones are significantly more recalcitrant to reduction by Sm(II). One question that arises from this work is whether the use of SmBr2-NMEA is mechanistically distinct from the Sm(II)water-Et3N system developed by Hilmersson. To test this question, 1d was treated with SmBr2-water-Et3N, yielding a mixture of products and unreacted starting material. This result contrasts with the recovery of only the cyclized product 2d from the reaction of 1d with SmBr2-NMEA (See Supporting Information). These observations are consistent with a difference in mechanistic pathway between the ET-PT observed for Sm(II)-water-Et3N compared to SmBr2-NMEA, which was demonstrated to proceed via PCET vide supra. Given the successful reduction of a broad scope of challenging substrates by SmBr2-NMEA, we considered whether the SmBr2-NMEA reagent could be applied to difficult substrate reductions of significant societal importance. Notably, the use of Sm(II)-water as a terminal reductant in the Mo-catalyzed fixation of N2 has been described by Nishibayashi and coworkers. We therefore investigated the reduction of analogs to intermediates in the nitrogen fixation process using SmBr2-NMEA. Azobenzene was found to be reduced rapidly to a give a quantitative yield of 1,2-diphenylhydrazine as shown in Scheme 7 (top). The stability of the N-N σ-bond against reduction by SmBr2-NMEA was hypothesized to be a consequence of steric interference by the two N-phenyl groups present in the substrate. Gratifyingly, reduction of phenylhydrazine to a quantitative yield of aniline by SmBr2-NMEA proceeded rapidly, as shown in Scheme 7 (bottom) with ammonia likely constituting the remainder of the product material.