There are some interesting aspects to it - such as using an electrically driven compressor so you can tailor the amount of compression to the Mach number. But that's an awful lot of hardware - keeping it light is going to be a big challenge (not to mention costs).
And of course, there is that always present problem with drag (and hence the thrust required) going up with the square of the speed. So even if you get very good SFC numbers, it's still going to take a lot more fuel to go that fast relative to today's ~0.8 Mach.