申请人:SYNGENTA PARTICIPATIONS AG
公开号:US20170217953A1
公开(公告)日:2017-08-03
The present invention relates to a process for the preparation of a compound of formula (I) wherein A
1
and A
2
are C—H, or one of A
1
and A
2
is C—H and the other is N; R
1
is C
1
-C
4
alkyl, C
1
-C
4
haloalkyl or C
3
-C
6
cycloalkyl; each R
2
is independently bromo, chloro, fluoro or trifluoromethyl; R
3
is hydrogen; R
4
is hydrogen, halogen, methyl, halomethyl or cyano; or R
3
and R
4
together form a bridging 1,3-butadiene group; R
5
is chlorodifluoro-methyl or trifluoromethyl; n is 2 or 3; by reacting a compound of formula (II) wherein A
1
, A
2
, R
1
, R
2
, R
3
, R
4
, R
5
and n is as defined under formula (I) above, with hydroxylamine, a base and a chiral catalyst, characterized in that the chiral catalyst is a dimeric chiral catalyst of formula (III) wherein R
6
, R
7
, R
8
, R
9
, R
10
and X are as defmed in claim
1
.