Acid-Catalyzed Transformations of 2-(Phenylethynyl)isoborneol

Author： Koval’skaya S. Kozlov N. Dikusar E.

ISSN： 1070-4280

Source： Russian Journal of Organic Chemistry, Vol.41, Iss.6, 2005-06, pp. : 832-837

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Abstract

2-(Phenylethynyl)isoborneol was synthesized by treatment of camphor with lithium phenylacetylide. Skeletal rearrangements of the title compound under the Ritter reaction conditions afforded a mixture of N-(4-phenylethynyl- and 4-benzoylmethyl-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl)acetamides at a ratio of 8:3. The reaction of 2-(phenylethynyl)isoborneol with formic acid involved mainly Meyer-Schuster rearrangement instead of the expected Rupe rearrangement, and the major product was 2-(1,7,7-trimethylbicyclo[2.2.1]hept-2-ylidene)-1-phenylethanone. The minor product (∼6%) was 1-(2-hydroxy-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl)-2-phenylethanone. The Ritter reaction of 2-(1,7,7-trimethylbicyclo[2.2.1]hept-2-ylidene)-1-phenylethanone selectively yielded N-(4-benzoylmethyl-1,7,7-trimethylbicyclo[2.2.1]hept-2-yl)acetamide.