Here is the configuration I use to make Drush working inside a Jailkit chrooted shell :

/etc/jailkit/jk_init.ini :

comment = the PHP interpreter and libraries
executables = /usr/bin/php5, /usr/bin/php
directories = /usr/lib/php5, /usr/share/php, /usr/share/php5, /etc/php5, /usr/share/php-geshi, [B]/usr/share/zoneinfo[/B]
includesections = env

comment = environment variables
executables = /usr/bin/env

comment = mysql client
executables = /usr/bin/mysql
paths = /usr/lib/x86_64-linux-gnu/

comment = drush (drupal command line)
includesections = php, mysql-client, uidbasics, netbasics
directories = /usr/share/zoneinfo, /etc/ssl/certs, /usr/share/ca-certificates

Once the jailed shell works, add the Drush dependencies to the jail :

jk_init -v -c /etc/jailkit/jk_init.ini -f -k -j /absolute/path/to/jail/ drush