*4.3. General Procedure for Preparation of Tetrahydroisoquinonolones* **9a**–**9u**

Step 1. Anhydride synthesis.

#### *Products* **9a**–**c** *and* **f**–**u**:

Diacid **10a**–**c**,**f** (50 mg) was mixed with DCM (1 mL, dry.) in a screw-cap vial, after which acetic anhydride (6 equiv.) was added to the suspension and the reaction mixture was stirred overnight at room temperature. Then, the solvent was evaporated in vacuo. The resulting crude anhydride was used in the next step without purification or characterization.

*For products* **9d**,**e***:*

Diacid 10c,f (50 mg) was dissolved in toluene (3 mL, dry) in screw-cap vial, after which acetic anhydride (6 equiv.) was added to the suspension and the reaction mixture was stirred overnight at 80 ◦C in a metal heating box. Then, the solvent was evaporated in vacuo. The resulting crude anhydride was used in the next step without further purification.
