Synced Photos not showing in Classic

I've recently started using Lightroom over the last year instead of Classic. However some edits I want to use NIK software or other plug-ins or do photostacks (things not avaible in Lightroom). I thought, since sync is enabled in both LR and LRC, I could access my photos uploaded to LR in LRC but the only photos in LRC are ones that I uploaded there directly. What am I doing wrong?

Thanks

Nate