Compound vs isolation exercises
Compound movements
If we are talking about building muscle or losing fat the exercises that are going to produce the greatest results are compound movements(Squat, bench, deadlift, pullup, dip, overhead press). These movements will recruit the most muscle fibers which is going to require more effort from your body as a whole which in turn will require more of a calorie demand for that session and throughout the day from the increase in metabolism from intense training. Performing compound movements is also going to allow you to put on the most muscle because again we are exposing more of the body to stress which after recovery will produce more muscle tissue growth.
Isolation movements
Isolation movements have their place as well. Sometimes we have imbalances that we need to bring up or touch up work on areas that are lagging behind. These movements should be performed after your compounds. There is a debate on if pre exhausting with a isolation exercise is beneficial to do before the compound because you're warming that area up and putting blood into that area. But your also taking out some gas in your gas tank that you are trying to reserve for the hard hitting compounds. Unless your coming back from a injury and need to properly that area up prior to working it to make sure its firing correctly or your an experienced lifter I don’t see the need to pre exhaust a muscle before doing a compound. That time and focus should be put into perfecting the technique and feel of your compounds. After your compounds if you feel you need to further target that area then that is the time to implement a isolation movement.