((3R,3 aR)-1-oxo-7-(3-oxomorpholin-4-yl)-1,3,3a,4-tetrahydrobenzo[b]oxazolo[3,4-d][1,4]oxazin-3-yl)methylmethanesulfonate 、
(3R,3aR)-3-(((tert-butyldimethylsilyl)oxy)methyl)-7-(3-oxomorpholino)-3a,4-dihydrobenzo[b]oxazolo[3,4-d][1,4]oxazin-1(3H)-one 、
邻苯二甲酰亚胺钾盐 、 以afforded white solid 2.76 g, yield: 82.1%的产率得到2-(((3S,3 aR)-1-oxo-7-(3-oxomorpholin-4-yl)-1,3,3a,4-tetrahydrobenzo[b]oxazolo[3,4-d][1,4]oxazin-3-yl)methyl)isoindolin-1,3-dione