固-液相转移催化α-芳磺酰基乙酸酯二烷基化

A Facile, Dialkylation of α-Arylsulfonylacetates under Solid-Liquid Phase Transfer Conditions

按预期的要求形成新碳-碳键的反应往往是有机合成中的关键步骤,在这方面含硫碳负离子起着重要作用。但要有效地产生必要的含硫碳负离子。

This paper reports a remarkably mild and convenient method for the generation ofα-arylsulfonylcarbanions and the dialkylations. Thus, α-arylsulfonylacetates(1 a～d) weretreated with potassium carbonate under solid-liquid phase transfer conditions to generate thecorresponding carbanions and then allowed to react in sitll with aikyl, allylic, and benzylichalides according to method A, B, or C. The alkylation proceeded very smoothly at 40℃ togive the dialkylated products(2～12) in good yields. Eleven dialkylated compounds weresynthesized and fully characterized by IR, ~1H NMR, MS, and elemerntal analysis. The mildreaction conditions, hence the tolerance of a variety of functional groups, the low moisturesensitivity and easier manipulation of potassium carbonate, and the flexibility in introducingvarious alkylating groups into the α-position of the substrates, according to method A, B,or C, make the present approach even more attractive and practieal for controlled carbon-carbon bond formation which is often a critical step in organic synthesis.