As far as I understand, Boukreev = Букреев , so it's Book-r-YE-yev (to me, as as speaker of Russian, the pronunciation and the stress are correct, and I see no other way a Russian could pronounce it).
I see. /bu'krʲejif/ or /bu'krʲeif/.
For example I don't pronounce voiced consonants at the end of words. Also I reduce unstressed vowels. krye is not convenient to pronounce either.