| Summary: | In this paper, we report the synthesis of spirocyclopropane-containing 4<i>H</i>-pyrazolo[1,5-<i>a</i>]indoles <b>6a</b>–<b>e</b> via alkylative dearomatization and intramolecular <i>N</i>-imination of indole–<i>O</i>-(methylsulfonyl)oxime <b>11</b>. Starting materials tryptophol (<b>7</b>) and 2-bromocyclopetanone (<b>8</b>) were reacted in the presence of HBF<sub>4</sub>·OEt<sub>2</sub>, providing 1,2,3,5,6,11-hexahydrocyclopenta[2,3]oxepino[4,5-<i>b</i>]indole (<b>9</b>) in a 63% yield. Compound <b>9</b> was reacted with hydroxylamine hydrochloride to afford oxime <b>10</b> (65% yield), which was subsequently bis-methanesulfonated to form <b>11</b> in a 85% yield. Heating <b>11</b> with various alcohols in the presence of <i>N</i>,<i>N</i>-diisopropylethylamine (DIPEA) triggered the alkylative dearomatization and intramolecular <i>N</i>-imination, forming the spirocyclopropane and 4<i>H</i>-pyrazolo[1,5-<i>a</i>]indole structures in the targets <b>6a</b>–<b>e</b> with 67–84% yields.
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