I don't think that sound exists in Portuguese. For me it was helpful to hear that it is pronounced in the same way as "y" in Swedish, or "i" in a particular dialect.
But if it is confusing, just prounounce it as "i" until you figure it out.
yes, in portuguese don't have some sounds, for exemple the sound of the letter Ж , we have the reference of the word in english "pleaSUre"

And this link is for 1000 most common words and you might listen to the words like какой, который, такой, человек to get the difference between the stressed O and unstressed one.
yeah, i saw, but there only the 50 first words have sounds.

Find me on Skype (MrEugene1000) to get the way it's pronounced explained
then right, here in Brazil , we don't use the Skype, we use the messanger or colloquialy called of MSN.
sorry =/