3-N-allyl-3-amino-3-C-cyano-3-deoxy-1,2-O-isopropylidene-3-N-methanesulfonyl-5-O-trityl-α-D-ribofuranose 在
caesium carbonate 作用下,
以
乙腈 为溶剂,
反应 1.33h,
以95%的产率得到1,2-O-isopropylidene-5-O-trityl-α-D-erythro-pentofuranose-3-spiro-3'-(2'-N-allyl-4'-amino-5'H-2',3'-dihydroisothiazole-1',1'-dioxide)