for the following products
(2R)-(-)-2,5-Dihydro-3,6-dimethoxy-2-isopropylpyrazine | (3R)-2,5-Dimethoxy-3-(methylethyl)-3,6-dihydropyrazine | (R)-2,5-Dihydro-3,6-dimethoxy-2-isopropylpyrazine | Schollkopf Reagent and (R)-2-Isopropyl-3,6-dimethoxy-2,5-dihydropyrazine
