A New Synthesis of 1-and 2-Chloronaphthalenes by an Annulation

Give mechanisms for the formation of 2 and 4 which account for the different reactivity patterns. 

From the Diterpene Carnosol to the Benzodiazepine Agonist Miltirone 

Identify the intermediate A and suggest a mechanism for the conversion of 1 into 2. 

Attempts to hydrolyse the ester 2 with either KOH/IfyO/MeOH at 50°C or LiOH/THF/IfyO at reflux or AcOH in quinoline at 120°C were unsuccessful, and the starting material was recovered unchanged. Use of KO Bu/DMSO at 40-60°C for 4 hours, however, followed by aqueous acid gave a mixture of four products, the major of which (80%) was shown to be the acid 3. Ether cleavage of 3 with BBr3/CH2Cl2 at room temperature proceeded rapidly (5 min), and while the catechol derivative could be isolated and characterised spectroscopically, it was rapidly oxidised in air to 4, the potent benzodiazepine agonist miltirone. 

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