Besides changing the spec to.. what is it now.. 6V => 19 volts, you still haven't specified the current level in amps that you will need. Why not? It is a major aspect of the design.
Anyway, try actually clicking on the link I provided and enter the specs into the little boxes. It will then tell you what device(s) will meet your specifications. Here is the link again:http://parametric.linear.com/html/step-up_(boost)_regulators
For example, I entered 3 to 6 volt input, 19 volt output, and 4 amps. It suggested a Linear chip called: LT3757A... as 3 to 40 volts input, 3 to 350 volts output, and up to 25 amps, depending on the voltage you want. Of course it does require using a small Inductor coil, but you still haven't explained why you are loath to use one. I already pointed out that voltage doublers have power (amps) limitations and offered the better design choice as being a booster circuit. They are small, easy to use and rather cheap.. so what's the problem?
Click on the device name, download the specs in PDF format, fill in the blanks and build it. If you want something already pre-built then you may have to shop around a bit.. and expect to pay 10X what the parts cost alone.
Sorry, that's the best I can do.