A New Class of Dianionic Sulfur-Ylides: Alkylenediazasulfites

Abstract

The compounds [[(thf)Li2-[H2CS(NtBu)2]]2] (1) and [((thf)Li2[(Et)-(Me)CS(NtBu)2])2] (2) can be synthesized in a two-step reaction. Firstly addition of an alkyllithium to sulfur diimide gives the diazaalkylsulfinate [RS(NtBu)2] (R =Me, sBu). In a second step the alpha-carbon atom in R is metalated with one equivalent of methyllithium to give the S-ylides. This new class of compounds can be rationalized as sulfite analogues, in which two oxygen atoms are each isoelectronically replaced by a NtBu group and the remaining oxygen atom is replaced by a CR2 group. Similar to Corey's S-ylides (R2(O)S+-CR2) and Wittig's phosphonium ylides (R3P+ - -CR2), these molecules contain a positively charged sulfur atom next to a carbanionic center. Therefore nucleophilic addition reactions of the carbon atom are feasible. The reaction of a sulfur diimide with the anionic carbon center in [H2CS-(NtBu)2]2- gives the intermediate alkylbis(diazasulfinate) [(tBuN)2SCH2S(NtBu)2]2-. The acidity of the hydrogen atoms at the bridging CH2 group is high enough to give, upon deprotonation, the [(tBuN)2SCHS(NtBu)2]3- trianion in [[(thf)Li3[(tBuN)2SCHS(NtBu)2]]2] (3). In [(Et)(Me)CS(NtBu)2]2 the nucleophilic carbon atom is sterically hindered and transimidation instead of deprotonation is observed. In a complex redox process [(thf)6Li6S((NtBu)3S]2] is recovered. The two new classes of compounds broaden the rich coordination chemistry of the triazasulfites by the introduction of a hard carbon center.

Imido-Analoga einfacher Oxoanionen: ein neuer Abschnitt in der Chemie der Clusterverbindungen

“…[43] 8. [98] Eine interessante Erweiterung der Studien über Imido-Analoga einfacher Oxoanionen ist die Synthese der Imido-Analoga von komplexen Oxoanionen wie Aluminosulfaten, [99] Aluminosilicaten [Al(SiO 4 )] À und Aluminophosphaten [Al(PO 4 ) 2 ] 3À . Strukturuntersuchungen an diesen Clustersystemen sollen vornehmlich dazu beitragen, diese Aggregationsprozesse zu verstehen und sie möglichst auch steuern zu können.…”

π-Spacer-coupled Diimidosulfinates

“…Previous investigations in our group showed that it is possible to connect two sulfurdiimides through 0932-0776 / 10 / 0600-0711 $ 06.00 c 2010 Verlag der Zeitschrift für Naturforschung, Tübingen · http://znaturforsch.com an organic spacer. Two sulfurdiimides and also two sulfurtriimides were coupled with a methylene bridge [27,28] or with a thiophene, dithiophene or selenophene bridge [29]. Fueled by these promising results, in the work presented in this paper we embarked to broaden the field of organic spacers ( Fig.…”

Syntheses and Electron Density Determination of Novel Polyimido Sulfur Ylides

“…Scheme 2-3b-d). [62] This fuels the dispute to which extent sulfur ylides are dominated by ylidic or ylenic bonding. Cleavages of formal S═N double bonds are found frequently in the literature.…”

“…Ten complexes of this kind have been synthesized and crystallized so far. [61][62][63][64][65] The additional carbanionic site takes part in the coordination of the metal ion. While the sulfur(IV) species prefer to form dimers for an enhanced coordination of the lithium cations, the only known sulfur(VI) species remains monomeric.…”

“…[64,66] In addition to their coordination chemistry, polyimido sulfur ylides are especially interesting, as they can be regarded as Corey ylides. [62,67,68] The advantage of using polyimido sulfur ylides instead of classical Corey ylides is the capability to transfer the carbon or alternatively the imido substituents, depending on the reaction conditions. [69,70] This will be discussed further in chapter 2.1.…”