A compound selected from the group consisting of (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(5-fluoro-1-methyl-1 H -pyrazol-3-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-[1-(2,2,2-trifluoroethyl)-1 H -pyrazol-4-yl]-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(5-methyl-1,2,4-oxadiazol-3-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(4-fluoro-1-methyl-1 H -pyrazol-3-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(2-methyl-2 H -1,2,3-triazol-4-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-6-[4-(Difluoromethyl)-1,3-oxazol-2-yl]-8a-(2,4-difluorophenyl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-[1-( 2 H 3)methyl-1 H -pyrazol-4-yl]-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(1-methyl-1 H -1,2,3-triazol-4-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; 2-[(4a R,6 R,8a S)-2-Amino-8a-(2,4-difluorophenyl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-6-yl]-1,3-oxazole-4-carbonitrile; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(5-methylpyrazin-2-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a S,6 S,8a R)-8a-(2,4-Difluorophenyl)-6-(5-methylpyrazin-2-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(5-ethoxy-1-methyl-1 H -pyrazol-3-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4 S,4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-4-(fluoromethyl)-6-(3-methyl-1,2-oxazol-5-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4 R,4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-4-methyl-6-(3-methyl-1,2-oxazol-5-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4 R,4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-4-methyl-6-(1-methyl-1 H -pyrazol-4-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4 S,4a R,6R,8aS)-8a-(2,4-Difluorophenyl)-4-(fluoromethyl)-6-(1-methyl-1 H- pyrazol-4-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(5-fluoropyridin-2-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; 5-[(4a R,6 R,8a S)-2-Amino-8a-(2,4-difluorophenyl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-6-yl]-1-methylpyridin-2(1 H)-one; rel-(4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(6-methylpyridin-3-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(5-methoxypyrimidin-2-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(2-methylpyrimidin-5-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(pyrimidin-5-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(2-methoxypyridin-4-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(5-methoxypyridin-3-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(2-methylpyridin-4-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4aR,6R,8aS)-8a-(2,4-difluorophenyl)-6-(5-fluoropyridin-3-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4-d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(imidazo[1,2-a]pyrimidin-2-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-([1,3]oxazolo[4,5- c]pyridin-2-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-([1,3]oxazolo[5,4- c]pyridin-2-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; and (4a R,6 R,8a S)-8a-(2,4-Difluorophenyl)-6-(imidazo[1,2-a]pyridin-6-yl)-4,4a,5,6,8,8a-hexahydropyrano[3,4- d][1,3]thiazin-2-amine; or a tautomer thereof or a pharmaceutically acceptable salt of said compound or tautomer.