Strategy of a game
If at any time Bob chooses $1$ then Alice chooses $97$ and wins. So in the following I will ignore this choice for Bob.
Alice wins by playing $62$. There are two possibilities.
Bob chooses $31$
Alice now forces the following sequence where Alice's choices are asterisked. She always chooses a product of two primes greater than $50$ where one of the primes has already been used and so Bob has no choice (other than $1$).
$*93*,3,*51*,17,*85*,5,*95*,19,*57*$ and now $1$ is forced.
Bob chooses $2$
Alice now forces the following sequence.
$*58*,29,*87*,3,*51*$ and now as in the above sequence.