The present invention relates to a process for preparing a compound of formula I,
wherein
R
1
is Pg
1
or P
1
′;
P
1
′ is CO-hydrocarbyl;
P
2
is CH
2
, O or N-Pg
2
; and
Pg
1
and Pg
2
are each independently nitrogen protecting groups;
(i) reacting a compound of formula II with a dioxirane to form an epoxide of formula III;
where X is selected from CN, CH
2
N
3
, CH
2
NH-Pg
2
, ONH-Pg
2
, NHNH-Pg
2
, N(Pg
2
)NH-Pg
2
;
(ii) converting a compound of formula III to a compound of formula I
本发明涉及一种制备式I化合物的方法,其中R1为Pg1或P1';P1'为CO-烃基;P2为
CH2、O或N-Pg2;而Pg1和Pg2各自独立地为氮保护基;(i)反应式II的化合物与二氧杂环烷反应,形成式III的
环氧化物;其中X选择自CN、 N3、 NH-Pg2、ONH-Pg2、NHNH-Pg2、N(Pg2)NH-Pg2中的一个;(ii)将式III的化合物转化为式I的化合物。