双丙酮半乳糖 、
Acetic acid (3aS,5R,6R,7R,7aS)-6-acetoxy-5-acetoxymethyl-2-trichloromethyl-5,6,7,7a-tetrahydro-3aH-pyrano[3,2-d]oxazol-7-yl ester 在
三氟甲磺酸三甲基硅酯 、 4 A molecular sieve 作用下,
以
二氯甲烷 为溶剂,
以87%的产率得到Acetic acid (2R,3R,4R,5S,6S)-3-acetoxy-2-acetoxymethyl-6-((3aR,5R,5aS,8aS,8bR)-2,2,7,7-tetramethyl-tetrahydro-bis[1,3]dioxolo[4,5-b;4',5'-d]pyran-5-ylmethoxy)-5-(2,2,2-trichloro-acetylamino)-tetrahydro-pyran-4-yl ester