The scope of the reductive-alkylation of chiral endo-himimide derived from (R)-phenylglycinol was studied. Careful structural studies by means of both X-ray crystallographical analysis and H-1 NMR spectroscopy analysis on the intermediates and products obtained during these studies allowed us to assign the structures of all the products obtained, and then to conclude that both the Grignard reagents addition (to 1) and the reductive deoxygenation of 2/3 via N-acyliminium intermediates A occurred stereospecifically from the convex face of either 1 or A.