You'd be an idiot to attempt that using just a jack. Axle stands needed. Unless you're skinny, if the cars not lowered might be able to get to them.
I managed to fit under mine when it was lowered. Only need your chest under.
Yh that involves getting right under the car lol. Unless your really skinny?
My Clio is lowered on sportlines. Jacked the rear end up with a trolly jack and managed to slip my 13 stone frame under the car with little difficulty. Could easily have got the cat and exhaust off if necessary. Getting them back on correctly on the other hand...............