Sommelet—Hauser

Another indole/oxindole synthesis achieves the critical ortho-substitution by Sommelet-Hauser rearrangement of an anilinosiilfonium ion intermediate. Use of P-thioketones (G = R, an alkyl group) generates 2-substituted indoles, whereas P-thioesters (G = OR) lead to oxindoles. In each case, a 3-thio substituent must be removed by desulfuri2ation. 

SOMMELET HAUSER Ammonkjmyfld rearrangement Rearrangement of quaternary ammonium ylids to aminas by aryl trarafer. 

The mechanism of the indolization of aniline 5 with methylthio-2-propanone 6 is illustrated below. Aniline 5 reacts with f-BuOCl to provide A-chloroaniline 9. This chloroaniline 9 reacts with sulfide 6 to yield azasulfonium salt 10. Deprotonation of the carbon atom adjacent to the sulfur provides the ylide 11. Intramolecular attack of the nucleophilic portion of the ylide 11 in a Sommelet-Hauser type rearrangement produces 12. Proton transfer and re-aromatization leads to 13 after which intramolecular addition of the amine to the carbonyl function generates the carbinolamine 14. Dehydration of 14 by prototropic rearrangement eventually furnishes the indole 8. 

Benzylic quaternary ammonium salts, when treated with alkali metal amides, undergo a rearrangement called the Sommelet-Hauser rearrangementSince the product is a benzylic tertiary amine, it can be further alkylated and the product again subjected to the rearrangement. This process can be continued around the ring until an ortho position is blocked. ... 

For a method that uses nonbasic conditions, and gives high yields of the Sommelet-Hauser product, with little or no Stevens rearrangement, see Nakano, M. Sato, Y. J. Org. Chem., 1987, 52, 1844 Shirai, N. Sato, Y. J. Org. Chem., 1988, 53, 194. 

Ammonium ylides can isomerize to (1,2) rearrangement products (Stevens rearrangement) or to (2,3) shift products (Sommelet-Hauser sigmatropic rearrangement) when allyl or benzyl are located on the nitrogen atom. A strong microwave effect is noticed (Eq. 66) [116]. 

Transformation of allyl ethers into homoallylic alcohols by treatment with base. Also known as Still-Wittig rearrangement. Cf. Sommelet-Hauser rearrangement... 

An effective method of hexahydrothieno[3,2-c]- and [2,3-c]azocines 146 and 148 syntheses involving a Sommelet-Hauser rearrangement of l,l-dimethyl-2-(2- or 3-thienyl)pyrrolidine salts 145 and 147 under the action of NaNH2 in liquid ammonia has been described (87SC935 Scheme 40). 

Durch eine Umlagerung vom Sommelet-Hauser-Typ (vgl. S. 1149) erhalt man beim Erhitzen von N-Aryl-S,S-dimethyl-sulfiliminen in Gegenwart von Triethylamin oder an-deren Basen oder auch Succinimid 2-(Methylthio-methyl)-aniline z. B. 4-Chlor-2-(methylthio-methyl)-anilin (95%)4 bzw. 6-(Methylthio-methyl)-2-trifluormethyl-anilin ( 100%)5 ... 

Amine aus N-Yliden durch Stevens- bzw. Sommelet-Hauser-Umlagerung... 

Die in Bd.XI/1, S.908 erwahnte Sommelet-Hauser-Umlagerung von Benzyl-trime-thyl-ammonium-Salzen zu Dimethyl-(2-methyl-benzyl)-amin ist fur das Jodid in Lit.3 aus-fiihrlich beschrieben. 

Anders verlauft die durch Fluorid-Ion (Casiumfluorid) bewirkte Umlagerung von Benzyl-dia]kyl-(trimethylsilyl-methyl)-ammonium-halogeniden. Hauptprodukt ist in diesem Fall das durch Desilylierung und Sommelet-Hauser-Reaktion entstandene 2-(Dialkyl-amino-methyl)-l-methyl-benzol(I) neben zumeist sehr geringen Mengen (wenige Prozent) an dem durch Stevens-Reaktion entstandenen l-Dialkylamino-2-phenyl-ethan(II)1,2. 

The Sommelet-Hauser rearrangement competes when Z is an aryl group (see 3-26). Hofmann elimination competes when one of the R groups contains a 0 hydrogen atom (7-6 and 7-7). 

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