I have the following statement in Rails 3 using an SQLite3 database:
word = \'Hello\' word_entry = Word.where(\"name REGEXP :word\", {:word => \"[[:<:]
I ran into the same issue. I took the code used in the resolution, ported it to work with Rails 3+ and made a gem for easier use. I hope this helps.
https://github.com/sei-mi/sqlite3_ar_regexp