“…119−128 The role played by a divalent metal ion such as magnesium may be the activation of the substrate and the 1,4-dihydronicotinamide, as well as the stabilization of the transition state. 129,130 mNADHs, especially MNAH, PNAH, and BNAH, have been used in the reduction of a wide range of compounds (Scheme 14), such as α-keto esters, 121,131,132 α-diketones, 133 α-hydroxy ketones, 133 trifluoroacetophenone, 134,135 benzaldehydes and acetophenone, 136 2-acylpyridines, 137 and cinnamoylpyridines (with Mg 2+ or Zn 2+ ). 138 The reduction of different imines to amines has also been carried out, with α-imino esters, 139 αimino acids, 140 α,β-unsaturated iminium salts, 141 and reductive aminations.…”