Complex shell scripts in kernel.core_pattern are not working

Issue

Simple scripts in /proc/sys/kernel/core_pattern work properly but as soon as more complex scripts with spaces are used they seem to be ignored.

The following script works:

# cat core.sh
#!/bin/sh
gzip -c -1 > /tmp/core.gz
# echo "|/root/core.sh" > /proc/sys/kernel/core_pattern 
[root@00559414-server ~]# ./a.out 
Segmentation fault (core dumped)
[root@00559414-server ~]# ls -l /tmp/core.gz 
-rw-r--r--. 1 root root 17794 Mar 19 13:42 /tmp/core.gz

The following will not work:

# echo "|/bin/sh -c \"gzip -c -1 > /tmp/core2.gz\"" > /proc/sys/kernel/core_pattern
[root@00559414-server ~]# ./a.out 
Segmentation fault (core dumped)
# ls -l /tmp/core2.gz
ls: cannot access /tmp/core2.gz: No such file or directory