Convenient Synthesis of Triphenylphosphanylidene Spiro[cyclopentane-1,3′-indolines] and Spiro[cyclopent[2]ene-1,3′-indolines] via Three-Component Reactions

Three-component reactions of triphenyl­phosphine,
but-2-ynedioate,
and isatylidene malononitrile (ethyl cyanoacetate) in dimethoxyethane
resulted in triphenyl­phos­phanyli­dene spiro­[cyclo­pentane-1,3′-indolines]
in satisfactory yields. Furthermore, similar three-component reactions
of triphenylphosphine, hex-2-en-4-ynedioate, and isatylidene malononitrile
(ethyl cyanoacetate) afforded functionalized spiro­[cyclo­pent[2]­ene-1,3′-indolines]
in good yields.