(2R,3S,4R,5R,6S)-3,4,5-Tris-benzyloxy-2-benzylsulfanyl-6-methyl-tetrahydro-pyran 、
methyl 6-[(2R,3R,4R,5S,6R)-4-[[(4aR,6R,7R,8S,8aS)-2-phenyl-7,8-bis(phenylmethoxy)-4,4a,6,7,8,8a-hexahydropyrano[3,2-d][1,3]dioxin-6-yl]oxy]-6-[[tert-butyl(diphenyl)silyl]oxymethyl]-3-hydroxy-5-(4-oxopentanoyloxy)oxan-2-yl]oxyhexanoate 在
molecular sieve 、 (dimethylthio)methylsulfonium trifluoromethanesulfonate 作用下,
以
二氯甲烷 为溶剂,
以92%的产率得到methyl 6-[(2R,3R,4S,5S,6R)-4-[[(4aR,6R,7R,8S,8aS)-2-phenyl-7,8-bis(phenylmethoxy)-4,4a,6,7,8,8a-hexahydropyrano[3,2-d][1,3]dioxin-6-yl]oxy]-6-[[tert-butyl(diphenyl)silyl]oxymethyl]-3-[(2S,3S,4R,5R,6S)-6-methyl-3,4,5-tris(phenylmethoxy)oxan-2-yl]oxy-5-(4-oxopentanoyloxy)oxan-2-yl]oxyhexanoate