1027952-56-2Relevant academic research and scientific papers
Experimental and theoretical investigation of the coarctate cyclization of (2-ethynylphenyl)phenyldiazenes
Shirtcliff, Laura D.,Weakley, Timothy J. R.,Haley, Michael M.,Koehler, Felix,Herges, Rainer
, p. 6979 - 6985 (2007/10/03)
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 under neutral conditions, at moderate temperatures, and without the requirement of a carbene stabilizer. A wide variety of previously unknown diazene precursors was synthesized and cyclized. Trapping of 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] cycloadduct with 2,3-dimethyl-2- butene.
