Ring-closing reaction of allenic/propargylic anions generated by base treatment of sulfonylallenes.
The intramolecular trapping of allenyl/propargyl anions generated by base treatment of sulfonylallenes was investigated. Treatment of 1-(omega-iodoalkyl)-1-(phenylsulfonyl)allenes with TBAF or NaH in DMF efficiently produced three- to seven-membered 1-ethynyl-1-(phenylsulfonyl) substituted carbocycles. The allenyl/propargyl anions could also be intramolecularly trapped using a terminal aldehyde or alpha,beta-unsaturated ester. The phenylsulfonyl group was found to be replaced by other electron-withdrawing functionalities like ketone and ester groups but not by an alkyl group for this novel ring-closing reaction.
Kitagaki
Shinji
S
Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kakuma-machi, Kanazawa 920-1192, Japan.
Teramoto
Satoshi
S
Mukai
Chisato
C