[3 + 2] Cyclization-elimination route to cyclopentenyl sulfones using (phenylsulfonyl)-1,2-propadiene
摘要:
Treatment of (phenylsulfonyl)-1,2-propadiene (1) with bis(phenylsulfonyl)methane in the presence of sodium hydride affords 2,4,4-tris(phenylsulfonyl)-1-butene in 94% yield. Similar rearranged products were obtained using other soft nucleophiles and related allenes. The formation of these products involves addition of benzenesulfinate anion onto allene 1. The initially formed carbanion undergoes proton transfer with bis(phenylsulfonyl)methane followed by a S(N)2' reaction of the resulting anion with 2,3-bis(phenylsulfonyl)-1-propene. Supporting evidence for the proposed mechanism is provided by the observation that the reaction of dimethyl malonate with the activated allene in the presence of sodium benzenesulfinate gives mostly abnormal products. When allene 1 is allowed to react with olefins bearing an electron-withdrawing group in the presence of sodium benzenesulfinate, a substituted cyclopentenyl sulfone is formed. The reaction proceeds in a stepwise fashion by addition of the initially produced carbanion onto the activated pi-bond of the olefin followed by a 5-endo-trig cyclization and elimination of benzenesulfinate. This approach represents a mild and versatile anionic [3 + 2] route to five-membered unsaturated sulfones.
Synthesis of cyclopentenyl sulfones via the [3 + 2] cyclization-elimination reaction of (phenylsulfonyl)allene
作者:Albert. Padwa、Philip E. Yeske
DOI:10.1021/ja00213a042
日期:1988.3
PADWA, ALBERT;YESKE, PHILIP E., J. AMER. CHEM. SOC., 110,(1988) N 5, 1617-1618
作者:PADWA, ALBERT、YESKE, PHILIP E.
DOI:——
日期:——
[3 + 2] Cyclization-elimination route to cyclopentenyl sulfones using (phenylsulfonyl)-1,2-propadiene
作者:Albert Padwa、Philip E. Yeske
DOI:10.1021/jo00022a032
日期:1991.10
Treatment of (phenylsulfonyl)-1,2-propadiene (1) with bis(phenylsulfonyl)methane in the presence of sodium hydride affords 2,4,4-tris(phenylsulfonyl)-1-butene in 94% yield. Similar rearranged products were obtained using other soft nucleophiles and related allenes. The formation of these products involves addition of benzenesulfinate anion onto allene 1. The initially formed carbanion undergoes proton transfer with bis(phenylsulfonyl)methane followed by a S(N)2' reaction of the resulting anion with 2,3-bis(phenylsulfonyl)-1-propene. Supporting evidence for the proposed mechanism is provided by the observation that the reaction of dimethyl malonate with the activated allene in the presence of sodium benzenesulfinate gives mostly abnormal products. When allene 1 is allowed to react with olefins bearing an electron-withdrawing group in the presence of sodium benzenesulfinate, a substituted cyclopentenyl sulfone is formed. The reaction proceeds in a stepwise fashion by addition of the initially produced carbanion onto the activated pi-bond of the olefin followed by a 5-endo-trig cyclization and elimination of benzenesulfinate. This approach represents a mild and versatile anionic [3 + 2] route to five-membered unsaturated sulfones.