A Route to ortho-Substituted Benzyne Precursors by Deprotonation of 7- Methyl-1-aminobenzotriazole Derivatives.

Double deprotonation of N-Boc-7-methyl-1-aminobenzotriazole 6 using nBuLi-TMEDA-THF [−78°C - > 0°C] results in an essentially quantitative conversion to the dianionic intermediate 7. Trapping at the carbon-centred anion occurs selectively under suitable conditions with alkylating agents, aldehydes and ketones to give good to excellent yields of the 7-substituted-1-aminobenzotriazoles 8–15, precursors of ortho-substituted benzynes.