It is not as simple as you think!
1. The peak inductor current requirement is large. You will have a hard time to find a commercial inductor which supports ~6A without core saturation. Can your battery supply a peak current of 6A?
2. C1 must be much larger to filter the pulses, even though I raised the switching frequency to 50Khz. Note the gate drive duty cycle to get ~45V out.
3. The NFET drive requirements are critical: Gate Driver impedance MUST be very low (see the 47Ω (R3), otherwise the gate capacitance will slow the rise/fall time of the gate signal, slowing the FET switching times, causing HUGE dissipation in the FET. The amplitude of the gate drive must be sufficient to saturate the FET. Typical gate drive level is 10V. Logic-level FET might allow 5V gate drive; 4.5V will be marginal.
4. The power dissipation of the NFET is ~2W, so it will have to be heatsinked.