Answer Happy

In order to unlock the cancer-killing properties of the compound dynemicin A, both an epoxide must be opened and a nucleophile must be added. These events occur after dynemicin A has been reduced to A. Can you propose a mechanism to account for this final conversion, noting that direct, SN2-like opening of the epoxide by that nucleophile is not possible since both positions are fully substituted in the starting material? (See: Tetrahedron Lett. 1990, 31, 151; Biochemistry 1991, 30, 2989; Angew. Chem. Int. Ed. 1991, 30, 1387) НО OHN HO OH H₂ OH о но dynemicin A 0 OX OH HN OH он HN Me H CO₂H OH OMe Он CH₂ H CH₂ H CO₂H O–CH, CO₂H H, HO HO HN Add curved arrow(s) to draw steps of the mechanism. Be sure to include relevant stereochemistry at all chiral centers by using the dashed and wedged bond tools to draw new bonds (the direction of these bonds can be changed by clicking on a drawn bond). OCH, HO HO HO OH A O OH ✔ Edit Drawing OH Me 11 H* H OH CO₂H OMe OH ای ایرانی به OH CH₂ CO₂H Arc HN HN HOM OH CH₂ HO HO HN H OH НО НО НО O-CH H₂ CO₂H HO OCH, Me NU CO₂H OMe