Chemistry of allenic/propargylic anions generated by base treatment of sulfonylallenes: synthesis of 1-alkynyl-1-sulfonylcycloalkanes and cycloalkanols

The intramolecular trapping of allenyl/propargyl anions, generated from sulfonylallenes with the proper base, by a haloalkyl group or an aldehyde functionality was investigated. The treatment of 1-(ω-iodoalkyl)-1-(phenylsulfonyl)allenes with TBAF or NaH in DMF efficiently produced the 1-alkynyl-1-(phenylsulfonyl)-substituted three- to seven-membered carbocycles. The allenyl/propargyl anions could also be intramolecularly trapped using a terminal aldehyde to stereoselectively afford the 2-alkynyl-2-(phenylsulfonyl)-substituted five- and six-membered cycloalkanols. The latter reaction could be performed using a catalytic amount of TBAF or DBU.