Gerhard Himbert

Intramolekulare diels-alder-reaktion bei allencarbonsäure-arylestern

Abstract By thermolysis aryl allenecarboxylates 6 and 7 undergo the intramolecular Diels-Alder reaction whereby the aromatic nucleus functions as diene. The lactones 8 and 9 are formed.

Nicht-symmetrische (butadiin)diamine

Abstract By successive treatment with butyllithium, bromine cyanide and secondary aliphatic amines the N-(3,4,4-trichloro-3-buten-1-ynyl)anilines 4 are transformed into the butadiynes, 7 , bearing two different amino groups. They react differently fast with electrophiles thus leading to the products 9 and 10 with one intact aminoacetylene unit.

The retro-diels-alder-reactivity of 1,4,3-oxathiazin-4-oxides

Abstract 1,4,3-oxathiazin-4-oxides 3 and 8 , formed by (4+2) cycloaddition of ynamines 1a–d or phenylacetylene 7 with N-sulfinyl-p-toluamide 2 , furnish p-tolunitrile 5 and the acyl-sulfines 4 and 9 by a retro-Diels-Alder reaction.

α-ACYL-SULFINES BY REACTION OF ACETYLENES WITH N-SULFINYL-AMIDES1

Abstract Ynamines, ynethers and phenylacetylene react with N-sulfinyl-carboxamides to give 1,4,3-oxathiazines, which tend to devide by a retro Diels-Alder reaction into nitriles and 2-sulfinyl-amides, 2-sulfinyl-esters and sulfinylacetophenone, resp.

Inimine und diinimine

Zusammenfassung Perchlorobutenyne 1 react with the methaneimines 2 to give the N-alkylidene-ynamines 3 . The trichlorovinyl group of 3a is transformed by butyllithium and a chlorosilane into a silylethinyl moiety (see 3a → 4 ). Some Cycloadditions of 3 and 4 are described.

S-Allyl(Propargyl)-S-Aryl(Hetaryl) Sulfides and Sulfones; Synthesis and Thermal Behaviour

Abstract Allyl(9-anthrylmethyl)sulfide and allenyl [1-naphthyl(or 2-furyl- or 9-anthryl-)methyl]sulfones undergo the Intramolecular Diels-Alder reaction.

Synthese von arsino-ketenen auf dem inether-weg

Abstract The arsino ketenes 3a–c are formed by the reaction of the arsino ynethers 1a and b with chlorodiphenylarsine and bromotriphenylgermane and by the reaction of the silylated ynether 1c with chlorodiphenylarsine.

Novel, five-membered cyclic betaines from the reaction of an ethynyl-hydrazine with aryl isothiocyanates

Abstract (Trimethylsilylethynyl)trimethylhydrazine 1 reacts with the aryl isothiocyanates 6 to give the corresponding 5-arylimino-1,1,2-trimethyl-4-trimethylsilyl-3-thioxo-pyrazolidinium-4-ides 7, which can be desilylated by fluoride ion to furnish the H bearing betaines 10 (= 7, but H instead of Me 3 Si).

Cycloadditionen, XX Thermisch induzierte intramolekulare Reaktionen bei 2-Methyl-2,3-butadienamiden / Cycloadditions, XX Thermally Induced Intramolecular Reactions of 2-Methyl-2,3-butadienamides

The 2-methyl-2,3-butadienamides 4a—m are directly synthesized by the reaction of the corresponding allenic acid chloride 2 with the secondary amines 3. At heating, 4a—j undergo the intramolecular Diels-Alder reaction, by using their ω-standing double bond and the π-system of the directly bonded phenyl groups or of the “methylenic” bonded arenes or furans. Thereby the tricycles 6a—g (bearing five-membered lactam moreties) and/or the tricycles 7-9 (bearing six-membered lactam moreties) are formed. The influence of the geminai methyl group on the chemoselectivity and on the velocity of the IMDA reactions is investigated. The N-allyl derivatives of 4 (s. 41 and m) form the bicycles 10 by intramolecular [2+2]-Cycloaddition.

Cycloadditionen, XIX. Umsetzungen von Butadiinyl- und Hexatriinyl-amin-Derivaten mit Nitriloxiden /Cycloadditions, XIX. Reactions of Butadiynyl- and Hexatriynyl-amine Derivatives with Nitrile Oxides

Butadiyn- and hexatriynamines 1 a - g, bearing silyl-, trichlorvinyl- and amino groups, resp. in the ω-position of their acetylenic system add nitrile oxides 3 at their first C/C-triple bond to give the 5-aminoisoxazoles 4, whereas the analogous oligoynamines 1 i-l, bearing a hydrogen in the ω-position, add the nitrile oxides 3 at their terminal C/C-triple bond to give the (5-isoxazolyl)ethynyl- or -1,3-butadiynyl-amines 7. The latter ones react with a second molecule of nitrile oxide 3 to give the bis(isoxazoles) 8. In two cases, keton oximes 6e,j are formed as the products of a 1,3-addition.