ethyl 4,5,7-tri-O-benzyl-2,3-di-deoxy-8-O-[ethyl (4,5,7,8-tetra-O-benzyl-3-deoxy-3-iodo-α-D-manno-2-octulopyranosyl)onate]-α-D-manno-2-octonate 1-S-oxido-1,3-propylene dithioketal 在
草酰氯 、 4 A molecular sieve 、
silver trifluoromethanesulfonate 作用下,
以
二氯甲烷 为溶剂,
以77%的产率得到ethyl {4,5,7-tri-O-benzyl-2,3-dehydro-8-O-[ethyl (4,5,7,8-tetra-O-benzyl-3-deoxy-3-iodo-α-D-manno-2-octulopyranosyl)onate]-α-D-manno-2-octulopyranosyl}onate