Palladium-Catalyzed 3 + 2 Synthesis of Cyclopentadienone Acetals

摘要

Substituted cyclopentadienone acetals (CPDAs) were synthesized by a palladium-catalyzed [3 + 2] cycloaddition of a substituted cyclopropenone acetal to an electron-deficient acetylene.As concemes the metal-catalyzed ring-cleavage/cycloaddition reactions of cyclopropenes,the present reaction provides a uniqaue example of a [3 + 2] reaction rather than a [1 +2] cycloaddition reaction leading to three-membered rings that has been the only reaction type thus far observed.