It's R. The methyl group is lowest priority, then you've got the ethyl group as third, hydroxy group as second and bromine first (based on atomic numbers). The photo shows the correct orientation for working out whether it's R or S (as the lowest priority is going in to the page). The priorities from highest to lowest are clearly going clockwise so it's R.
Similarly, you can have the lowest priority coming in to the page (wedged), work out whether the priorities are going clockwise or anticlockwise, and then flip the outcome. I think this is what you were getting at in the second part of your question, but you can only do it this way if the lowest priority substituent is coming INTO the page. (What you described ie. looking at the molecule from the right doesn't satisfy this, the methyl group isn't wedged but just pointing to the right)
· 4 months ago