[plt-scheme] immutable list r6rs

Hello,

I want to know how I can use immutable lists in r6rs.
This is because [style '(border)] gives the following error:
initialization for canvas%: expected argument of type <list of style 
symbols>; given {border}
my code is below:

(import (rnrs base (6))
        (only (scheme base) require))

(require  scheme/class)
(require scheme/gui/base)

(new canvas%
       [parent vp-left]
       [style '(border)]
       [label "playerhimstats"]
       [min-height 224])
  )