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Thioacetals are the sulfur analogue of acetals. They are prepared in a similar way to acetals: by reacting a thiol with an aldehyde: :RSH + R'CHO → R'CH(OH)SR Dithioacetals are prepared similarly to thioacetals, which are intermediates: :RSH + R'CH(OH)SR → R'CH(SR)2 + H2O Such reactions typically employ either a Lewis or Brønsted acid catalyst. Dithioacetals generated from aldehydes and 1,2-ethanedithiol are useful in organic synthesis: :C2H4(SH)2 + R'CHO → R'CHS2C2H4 + H2O Whilst the carbonyl carbon of an aldehyde is electrophilic, the ''deprotonated'' derivatives of dithioacetals feature nucleophilic carbon centers: :R'CHS2C2H4 + R2NLi → R'CLiS2C2H4 + R2NH Again, this reactivity is most commonly exploited in the 1,3-dithiolanes. The inversion of polarity between R'(H)Cδ+Oδ− and R'CLi(SR)2 is referred to as umpolung. ==See also== * Thioketal * Acetal * Mozingo reduction 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「thioacetal」の詳細全文を読む スポンサード リンク
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