Condensation of 2,3,4,6-tetra-O-(trimethylsilyl)-D-gluconolactone with tert-butyl[2-lithio-3,5-di-(triisopropylsilyloxy)benzyloxy]dimethylsilane, protection of the resultant spiroketal with di(tert-butyl)silyl di(trifluoromethanesulfonate), selective O-3′-esterification and deprotection gives papulacandin D.
2,3,4,6-四-O-(三甲基
硅基)-
D-葡糖醛内酯与叔丁基[2-
锂代-3,5-双(
三异丙基硅氧基)苯氧基]二甲基
硅烷缩合,所得螺
缩酮用二(叔丁基)
硅基二(
三氟甲磺酸)保护,选择性O-3′-酯化和脱保护得到皮刺芹二酮D。