Study On The Cyclization Of Functionalized Sulfoxides Based On α-Oxo Ketene Dithioacetals

As a kind of special alkenes with electron richα-carbon atom,α-oxo ketene dithioacetals have found their wide utilizations in organic synthesis during the past decades. It is clear that the highly polarized push-pull interaction on the C-C double bond of theseβ,β-dialkylthio-α,β-enones and analogues makes theirα-carbon atom a potential nucleophilic center.During the course of our studies on the chemistry ofα-oxo ketene dithioacetals, some useful methodologies and transformations have been achieved, and the nucleophilicity of theα-carbon atom has been recognized. So far, extensive work has revealed that a variety of organic reactions including Baylis-Hillman reaction,aza-Morita-Baylis-Hillman reaction,C-C coupling reaction and thiomethylation can be realized fromα-oxo ketene dithioacetals.As a kind of versatile synthons, sulfoxides have been widely used in organic synthesis.On the basis of our previous work, formaldehyde and thiols were chosen as carbon electrophiles , which can react withα-acetyl ketene-S,S-acetals in the presence of hydrochloric acid. Under the optimized conditions , a series of substitutedα,β- unsaturated sulfoxides were obtained.First, a series of thioethers were preparated on the basis of our recent work. It is observed that the reaction proceeded smoothly under the mild conditions to afford the corresponding thioethers in good yields.Second, we investigated the aldol reactions of the special thioethers with aromatic aldehydes under the mild conditions in good yields. Third, a Novel and facile method has been used to synthesize functionalized sulfoxides by the oxidation of thioethers.In the end, a facile synthesis of substitutedα,β-unsaturated sulfoxides has been developed based on the NaOH-mediated reactions of functionalized sulfoxides and intramolecular cyclization reactions.Forty-two new compounds were synthesized and characterlized by IR, Mass and NMR (1H, 13C) spectrum in this thesis.