A chiral 5-deazaflavin 1 with 2-hydroxynaphthyl group at N(3) position of the pyrimidine ring moiety was synthesized. 1 underwent, in the absence of magnesium ion, a ''(net) hydride transfer'' from BNAH to C(5) almost exclusively on the face where OH group is present. It was also the case with PNPH, and enantioselectivity for PNPH by 1 was higher in the absence of magnesium ion than in its presence. These results indicate that the ''diastereotopic face activation'' in 1 is operated as well as chiral recognition for PNPH by 1.