Synthesis of L-scyllo-inositol 1,2,4-trisphosphate, scyllo-inositol 1,2,4,5-tetrakisphosphate and phosphorothioate and DL-2-deoxy-2-fluoro-myo-inositol 1,4,5-trisphosphate: optical resolution of DL-1-O-allyl-3,6-di-O-benzyl-4,5-O-isopropylidene-scyllo-inositol