ARYNE CHEMISTRY OF PODOCARPIC ACID-DERIVATIVES

The anthranilic acid (2), a key intermediate for the generation of an aryne at C 13 of podocarpic acid derivatives, was synthesized from the 14-amino compound (5) which in turn was generated regiospecifically i n high yield by treatment of the 13-bromo compound (25) with sodamide in liquid ammonia. The amine was converted into the anthranilic acid b y two separate routes: firstly by directed lithiation and trapping of the lithium species with a CO2 moiety, and secondly by oxidative cleav age of an isatin fused across positions 13 and 14.