TY - JOUR
T1 - Synthesis and Biological Evaluation of O-Methylated Glycolipids Related to PGLs via Direct Stereoselective Glycosidation and Sequential Suzuki–Miyaura Coupling using Boracyclane
AU - Sato, Ko
AU - Omahdi, Zakaria
AU - Shibata, Kensuke
AU - Sonoda, Koh Hei
AU - Yamasaki, Sho
AU - Tanaka, Hiroshi
PY - 2017/11/16
Y1 - 2017/11/16
N2 - Synthesis of O-methylated glycolipids via direct stereoselective glycosidation whose sugar moieties are related to those in phenolic glycolipids (PGLs) is reported. Treatment of 2-O-methyl-rhamnosyl imidates with I2 and nBu4NOTf resulted in their activation under low temperature and provided the α-rhamnosides with excellent α-selectivity. nBu4NOTf enhanced the electorophilicity of iodine. This methodology improved the efficiency of the synthesis of both PGL-1 and PGL-tb1 sugars. The process involved the formation of 2-O-naphthylmethyl-α-rhamnoside and 2-O-methyl-α-fucoside. Sequential Suzuki–Miyaura coupling using synthetic glycosides, boracyclane, and aryl bromides provided glycolipids related to PGL sugars, and was accomplished with a one-pot process. Finally, we elucidated the immunosuppressive activities of all these synthetic compounds and found that a phenyl 3-O-α-rhamnosyl-2-O-methyl-α-rhamnoside possessing a 6-(2-naphthyl)hexyl group exhibited the strongest inhibitory effect.
AB - Synthesis of O-methylated glycolipids via direct stereoselective glycosidation whose sugar moieties are related to those in phenolic glycolipids (PGLs) is reported. Treatment of 2-O-methyl-rhamnosyl imidates with I2 and nBu4NOTf resulted in their activation under low temperature and provided the α-rhamnosides with excellent α-selectivity. nBu4NOTf enhanced the electorophilicity of iodine. This methodology improved the efficiency of the synthesis of both PGL-1 and PGL-tb1 sugars. The process involved the formation of 2-O-naphthylmethyl-α-rhamnoside and 2-O-methyl-α-fucoside. Sequential Suzuki–Miyaura coupling using synthetic glycosides, boracyclane, and aryl bromides provided glycolipids related to PGL sugars, and was accomplished with a one-pot process. Finally, we elucidated the immunosuppressive activities of all these synthetic compounds and found that a phenyl 3-O-α-rhamnosyl-2-O-methyl-α-rhamnoside possessing a 6-(2-naphthyl)hexyl group exhibited the strongest inhibitory effect.
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U2 - 10.1002/chem.201703684
DO - 10.1002/chem.201703684
M3 - Article
C2 - 28881056
AN - SCOPUS:85034055473
VL - 23
SP - 16374
EP - 16379
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 64
ER -