I have often come across reactions where kinetic and thermodynamic processes give completely different outputs. I was told that in such cases check temperature, if temperature controlled, then take thermodynamic product otherwise if reaction is very fast (not temperature controlled) then consider the kinetic product.
I was also told that if there is a case where you can't decide whether it is temperature controlled or speed controlled, then always take the thermodynamic product.
My question is: Why will thermodynamic processes have an upper hand in the latter case? CH2CHC(CH2)CH3 what MAJOR product does it produce on giving 1 equivalent HBr?