| Abstract
| - A new route to substituted 2-phenyl-2H-indazoles through the cyclization of (2-ethynylphenyl)phenyldiazenes is presented. A coarctate reaction pathway forms the isoindazole carbene underneutral conditions, at moderate temperatures, and without the requirement of a carbene stabilizer.A wide variety of previously unknown diazene precursors was synthesized and cyclized. Trappingof the carbene with a silyl alcohol followed by deprotection affords the 3-hydroxymethyl-2-phenyl-2H-indazoles in good overall yield. The free carbene could also be trapped as a [2 + 1] cycloadductwith 2,3-dimethyl-2-butene.
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