4,4-Dimethyl-1,4-thiasilinane and Its S-Functional Derivatives

Abstract

Synthetic approaches to 4,4-dimethyl-1,4-thiasilinane and its S-functional derivatives, 4,4-dimethyl-1,4-thiasilinane S-oxide, 4,4-dimethyl-1,4-thiasilinane S,S-dioxide, 4,4-dimethyl-1-(phenylsulfonylimino)-1,4-thiasilinane, and 1,4,4-trimethyl-1,4-thiasilinan-1-ylium iodide, were studied. The S-functional derivatives of 4,4-dimethyl-4-thiasilinane, unlike 3,3-dimethyl-3-thiasilinane, are hydrolytically stable.Thiasilinanes form an interesting class of heteroatomic cyclohexane derivatives. Thiasilinanes differ from earlier studied diheterocyclohexanes (dioxanes, dithianes, and oxathianes) in that they contain two heteroatoms of different nature: sulfur with a lone electron pair and silicon that exerts a strong inductive effect and, at the same time, has vacant d orbitals.Thiasilinanes have poorly been studied [136], while their S-functional derivatives have been unknown. In the course of the research into the properties and transformations of silathiacycloalkanes we have synthesized 3,3-dimethyl-1,3-thiasilinane S-oxide [7], 2,3,3-trimethyl-1,3-thiasilinane S-oxide, 2,3,3-tri-ÄÄÄÄÄÄÄÄÄÄÄÄ methyl-1,3-thiasilinane S,S-dioxide [8], 3,3-dimethyl-1-(phenylsulfonylimino)-1,3-thiasilinane, and 1,3,3-trimethyl-1,3-thiasilinan-1-ylium iodide [9, 10], and studied their transformations [10]. These works have primarily focused on 1,3-thiasilinanes; the only available information on 1,4-thiasilinanes related to the synthesis of 1,4-thiasilinane and its sulfonium salt, 1,4,4-trimethyl-1,4-thiasilinan-1-ylium iodide [4]. Proceeding with this research, in the present work we developed new synthetic approaches to 4,4-dimethyl-4-thiasilinane (I), synthesized their S-oxides II3V, and studied their hydrolytic stability.

Effects of methyl substitution in 4-silathiane S-oxides on the stereochemistry and1JCHcoupling constants: Buttressing effect of axial sulfinyl group as the origin of the reverse Perlin effect

“…Synthesis and isolation of all compounds (except for 5) is described elsewhere [11,12]. The 1 H and 13 summarized in tables 3 and 4.…”

“…Recently, we have described the synthesis of 4,4-dimethyl-4-silathiane and its S-functional derivatives including S-oxide [11]. Lithiation/methylation of the latter compound, 4,4-dimethyl-4-silathiane S-oxide 1, was shown to lead to the mono-and dimethylated derivatives.…”

“…In continuation of these studies in the present paper, we report on the structure, conformations and stereoelectronic interactions in the stereoisomers of 2,4,4-trimethyl-4-silathiane S-oxide 2ee and 2ae and 2,4,4,6-tetramethyl-4-silathiane S-oxide 3eee and 3aae based on a detailed 1 H and 13 C NMR analysis. For comparison, 4,4-dimethyl-4-silathiane S,S-dioxide 4 [11] and 2,4,4-trimethyl-4-silathiane S,S-dioxide 5 (synthesized in the present work) are also included. As will be shown below, these molecules are beneficial objects for analysis of stereoelectronic effects in six-membered rings.…”

Crystal structures and theoretical calculations of trans-2,4,4-trimethyl-4-silathiane 1-oxide and 4,4-dimethyl-4-silathiane 1,1-dioxide

“…Compounds 1 and 2 were prepared from 4,4-dimethyl-4-silathiane 1-oxide [3] as described in [5,7] according to Scheme 1. White crystals of 1 and 2 were obtained from CDCl 3 :CCl 4 (1:1).…”

“…Their first representatives, 3,3-dimethyl-3-silathiane 1-oxide and 2,3,3-trimethyl-3-silathiane 1-oxide, have been synthesized in our group more than 10 years ago [1,2]. Later on, 4,4-dimethyl-4-silathiane 1-oxide [3], 2,2,3,3-tetramethyl-3-silathiane 1-oxide, 2,4,4-trimethyl-4-silathiane 1-oxide, and 2,4,4,6-tetramethyl-4-silathiane 1-oxide were obtained [4], some of their diastereomers separated and isolated as individuals, and their chemistry [5] and stereochemistry studied [6,7]. A series of works on theoretical conformational analysis of various Si-substituted 4-silathiane 1-oxides has also been published [8][9][10][11].…”