The present invention pertains to a compound of formula (I)
1
wherein R
1
and R
2
are each (CH
2
)
m
X, each X is Cl or Br and m is 2 or 3, in combination with less than 0.5% w/w of the corresponding compound wherein R
1
is (CH
2
)
m
H. Such compounds can be prepared by (i) the reaction of a Bronsted acid or a Lewis acid with NaBH
4
in an organic solvent, and (ii) adding the resultant solution to a solution of a corresponding compound wherein one of R
1
and R
2
is CO(CH
2
)
n
X and the other is CO(CH
2
)
n
X or (CH
2
)
m
X, wherein n=m−1. Such compounds can also be prepared, in optically-enriched form, starting from an optically-enriched trihaloiminophosphorane of the formula R*N=Phal
3
wherein NR* is a chiral moiety derivable from a chiral amine or chiral sulphonamide of the formula R*NH
2
, which can be cyclisable with HO(CH
2
)
3
NHR.
本发明涉及一种式(I)的化合物,其中R1和R2均为(
CH2)mX,每个X为Cl或Br,m为2或3,与相应化合物中R1为( )mH的化合物相比,其含量小于0.5% w/w。这些化合物可以通过以下步骤制备:(i)用有机溶剂反应Bronsted酸或Lewis酸与NaBH4;(ii)将所得溶液加入其中一个R1和R2分别为CO( )nX和CO( )nX或( )mX的相应化合物的溶液中,其中n=m-1。这些化合物也可以以光学纯形式制备,其起始物为式R*N=Phal3的光学纯三卤代亚
磷酰胺,其中NR*是可由手性胺或手性磺酰胺的式R*NH2衍生的手性基团,可与HO( )3NHR环化。