Well, we never know... until we try. But no, I am not serious with my last sentence. No matter how ineffective chloroform might be seem, you'd better stay away of it.
Anyway, this might interest you
. It's more than a century old, but perhaps could give you some insight of the possibility of the usage. And anyway, when I read the article mct linked, chloroform is actually used and preferred for it gave quicker anesthetic effect compared to ether (though now other anesthesia is used for chloroform is anticipated as a human carcinogen - something that can give human cancer).
And I've checked wikipedia, and it shows that 10 mL (14.8 gram) is actually enough for you to have a death due to respiratory or cardiac arrest
And speaking of knocking man out with any kind of poison (whatever it could be - arsenic, chloroform, anything), it might never give quicker results than knocking out the man physically (like, for instance, by cosh). Poison (yes, any poison) takes time to react in the body, and depending on the man's immune system, the time the poison takes to react might vary for each man. While 10 mL of chloroform can give you death, it still takes time for reacting in your body.
but maybe if you got different types of chloroform, the strongest would probably be used on people.
If you are a thug who works with Mueller (who happened to have an access to high-concentrated chloroform), you might think the same. But like other high-concentrated chemicals, if you are a lone thug you definitely won't have any access to it (remember that it is very expensive and only sold to some consumers with specific needs - scientific, laboratory and industrial use).
I hope this post is clear enough to understand, if not, I am so sorry. *face palm*