I've got exactly the same problem. I bought a generic one from Amazon, which weirdly, works in my car, converting an old lightning cable, (generic, not Apple), to USB A. It plays audio and allows functionality of FF, RW, play etc from the head unit, and displays track and artist info to my cars standard head unit.
But when I try to use in my Bose SoundDock, it will not play, charge, or even recognise anything is plugged into it.
This is the one I bought from Amazon.
https://www.amazon.co.uk/dp/B0CLWT662W?psc=1&ref=ppx_yo2ov_dt_b_product_details
Now I just need to find one that works with my Bose unit...