对不同类别的环加成反应的综合研究([3+2],[2+2],使用密度泛函理论(DFT)和复合波函数方法进行了SO2对乙炔和乙烯的[21])。[3+2]环加成反应,先前在硫代甲醛S-甲基吡啶(TSM)与乙烯和乙炔的环加成的背景下进行了探索,以一致的方式形成稳定的杂环。在本文中,我们将我们的研究扩展到SO2向乙炔的[2+2]和[2+1]环加成,这将产生1,1-氧化硫-2-氧化物和噻吩-1,1-二氧化物,分别。主要结论之一是,环状1,1-氧化硫-2-氧化物可以通过相对容易地破坏SO单键而打开,并向亚磺酰基乙醛(SA)重排。SA分子可以很容易地进行一些内部重排,最终导致亚磺酸和亚乙基酮的亚砜衍生物,1,2,3-二氧硫酚,和CO加上亚磺酰基甲烷。最可能的路径,然而,产生2-硫代乙酸,其衍生物(或相应的乙酸盐的衍生物)通常通过Willgerodt-Kindler型乙酸盐的硫化获得。这种产品可以反过来分解,导致最终产品CO2和H2CS。该分解路径与2-氨基-2-硫代乙酸的分解路径的比较表明,该过程通过不同的H转移过程发生。
A comprehensive study of the different classes of cycloaddition reactions ([3+2], [2+2], and [2+1]) of SO2 to acetylene and ethylene has been performed using density functional theory (DFT) and composite wavefunction methods. The [3+2] cycloaddition reaction, that was previously explored in the context of the cycloaddition of thioformaldehyde S-methylide (TSM) to ethylene and acetylene, proceeds in a concerted way to the formation of stable heterocycles. In this paper, we extend our study to the [2+2] and [2+1] cycloadditions of SO2 to acetylene, which would produce 1,1-oxathiete-2-oxide and thiirene-1,1-dioxide, respectively. One of the main conclusions is that cyclic 1,1-oxathiete-2-oxide can open through a relatively easy breaking of the SO single bond and rearrange toward sulfinyl acetaldehyde (SA). The SA molecule can easily undergo several internal rearrangements, which eventually lead to sulfenic acid and sulfoxide derivatives of ethenone, 1,2,3-dioxathiole, and CO plus sulfinylmethane. The most probable path, however, produces 2-thioxoacetic acid, whose derivatives (or those of the corresponding acetate) are usually obtained by Willgerodt-Kindler-type sulfuration of acetates. This product can in turn decompose, leading to the final products CO2 and H2CS. Comparison of this decomposition path with that of 2-amino-2-thioxoacetic acid shows that the process occurs through different H-transfer processes.