[Johte]

This paper claims to open a lactone to a diol with LAH in THF at -78->0 . Addition of Rochelle's salt with subsequent pouring into a saturated solution thereof. That salt has carbonyls and alkoxides, I have no idea where the proton for the lactone reduction is coming from at this basic pH.

[TheUnassuming]

What proton are you referring to? 
Do you know the mechanism of LAH reduction?

[Johte]

http://www.adichemistry.com/organic/organicreagents/lah/lithium-aluminium-hydride-1.html This doesn't show the exact lactone, but it does show the 2 eq. abbreviated version. I have the mech from many books, March's, Carey's Adv Orgo, and some other Wiley publications. It's the H30⁺ workup.

It hit me like an NMR falling on me laying in bed last night. I assumed Rochelle's salt would not release a proton after the dissociation of Na⁺ and K⁺. It's purpose is to grab all the oxidized (?) AlH₃3⁺. Once those stabilize the two carboxylates I'm assuming at least one of the diols can dissociate.

[TheUnassuming]

 Yes, a proton source is needed to form the alcohol.  What is your Rochelle's salt dissolved in?

[discodermolide]

Work-up with Rochelle's salt in water is supposed to complex the aluminium hydroxide(s) formed and make it easier to remove the aluminium salts by filtration. It doesn't always work. If you have really long filtration times try using lithium borohydride as the reductant. Work-up is easier.

[Johte]

Yes, a proton source is needed to form the alcohol.  What is your Rochelle's salt dissolved in?

Always forgetting the details, Johte. It's aqueous, so yeah. Protons. For reference, without the Aluminum to stabilize the tartrate, Rochelle's salt would be basic in water?

[TheUnassuming]

Its ok, it happens to the best of us .
With or without Al, Rochelle's salt is basic.  The Al is just the counter ion.

[Johte]

Ok well, does the counter ion influence the release of protons? What I was trying to allude to was that without them it would just grab protons from water and not release any? I'm not wrapping my head around a basic salt as a proton source.

[TheUnassuming]

Ok well, does the counter ion influence the release of protons?

Release of protons from where?

So at the risk of being a bit too blunt, we are talking in circles.  Take a minute and type out the mechanism of what you think is happening in your reaction (including work up). 

Post it here.