Audio Extractor needed to convert ARC HDMI out to Optical out.

I have a projector that's connected to a 4K ATV and I want to send Dolby 5.1 over WiFi to a Sonos Beam 2 Soundbar on the opposite side of the room.

Yes the ATV can Airplay direct to the Sonos - but Airplay to the Sonos only supports stereo.

I have a Marantz NR1506 the same side of the room as the Sonos Soundbar, and fortunately the NR1506 supports Airplay with the full Dolby 5.1, but I have no optical out to accommodate the Sonos from the NR1506.

On the rear of the NR1506 is an HDMI ARC port - is there such thing as HDMI ARC to TOSLink extractor which will pass through the Dolby 5.1 sound over optical to the Beam 2?