(4a
S)-6
c-((5
R)-8
t-benzyloxy-2,2,6
c-trimethyl-(5
rO)-1,3,7-trioxa-spiro[4.4]non-9
c-yloxy)-2,2,7-trimethyl-(4a
r,6a
t,9a
c,9b
t)-hexahydro-[1,3]dioxino[4',5':5,6]pyrano[3,4-
d]oxazol-8-one 在
吡啶 、
溶剂黄146 作用下,
生成
(4aS)-6c-((5R)-8t-benzyloxy-6c-methyl-2-oxo-(5rO)-1,3,7-trioxa-spiro[4.4]non-9c-yloxy)-7-methyl-(4ar,6at,9ac,9bt)-hexahydro-[1,3]dioxino[4',5':5,6]pyrano[3,4-d]oxazole-2,8-dione