(4R,5S,6R)-5-Benzyloxy-4-hydroxy-2-methoxy-6-methyl-tetrahydro-pyran-2-carboxylic acid methyl ester 、
(4R,5R,6R)-4,5-Bis-benzyloxy-6-methyl-2-phenylsulfanyl-tetrahydro-pyran-2-carboxylic acid methyl ester 在
4 A molecular sieve 、
silver trifluoromethanesulfonate 作用下,
以
二氯甲烷 为溶剂,
以20%的产率得到methyl (4R,5R,6R)-2-[(4R,5R,6R)-2-methoxy-2-methoxycarbonyl-6-methyl-5-phenylmethoxyoxan-4-yl]oxy-6-methyl-4,5-bis(phenylmethoxy)oxane-2-carboxylate