Synthesis of Pyrido[1,2-b]indazoles via Aryne [3+2] Cycloaddition with N-Tosylpyridinium Imides

The [3 + 2] cycloaddition of arynes with N-tosylpyridinium imides, followed by an elimination of Ts-, affords pyrido[1,2-b]indazoles under mild reaction conditions in good yields.