allyl 3,4-di-O-benzoyl-α-L-rhamnopyranoside 、
(2,4-di-O-benzoyl-3-O-chloroacetyl-α-L-rhamnopyranosyl)-(1->3)-(2,4-di-O-benzoyl-α-L-rhamnopyranosyl)-(1->2)-3,4-di-O-benzoyl-α-L-rhamnopyranosyl trichloroacetimidate 在
4 A molecular sieve 、
三氟化硼乙醚 作用下,
以
二氯甲烷 为溶剂,
反应 1.25h,
以72%的产率得到allyl (2,4-di-O-benzoyl-3-O-chloroacetyl-α-L-rhamnopyranosyl)-(1->3)-(2,4-di-O-benzoyl-α-L-rhamnopyranosyl)-(1->2)-(3,4-di-O-benzoyl-α-L-rhamnopyranosyl)-(1->2)-3,4-di-O-benzoyl-α-L-rhamnopyranoside