COC1CC(OC2CC[C@@]3(C=O)C4CC[C@]5(C)C(C6=CC(=O)OC6)CC[C@@]5(O)C4CC[C@]3(O)C2)OC(C)C1O
An acid's negative base-10 logarithmic dissociation constant (pka) follows directly from its underlying thermodynamics; pKa is directly proportional to its standard Gibbs free energy change. What is the pka value of this molecule?