[AUCTeX] How to customize tex-mode-map to rebind TeX-electric-escape?..

[Leo Alekseyev]

Dear All,
I would like to use TeX-electric-macro, but I would like to rebind it
to C-\ (backslash).  I tried both of the following:
(define-key tex-mode-map [(control \\)] 'TeX-electric-macro)

and

 (add-hook 'TeX-mode-hook
          '(lambda ()
             (define-key tex-mode-map [(control \\)] 'TeX-electric-macro)))

However, in both cases I get an error "symbol's value as variable is
void: tex-mode-map".  Can anyone tell me what the correct procedure is
for rebinding the command?
Thanks,
--Leo