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1

Reaction of 1,2-Di(1-adamantyl)-2-thioxoethanone with Diazomethanes; 1,3- versus 1,5-Dipolar Electrocyclization of a Sterically Crowded Thiocarbonyl S-Methylide

Mlostoń G., Urbaniak K., Nomura T., Nakayama J., Heimgartner H.

Polish Journal of Chemistry

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2009

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Vol. 83, nr 11

1945-1951

EN

The reaction of 1,2-di(1-adamantyl)-2-thioxoethanone (4c) with diazomethane and 2-diazopropane yielded 2-acylthiiranes 6a and 6b, respectively, and no 1,3-oxathioles of type 7 were formed. The reaction course is explained via [2+3]-cycloaddition, elimination of N2, and 1,3-dipolar electrocyclization of the in ter me di ate acyl-substituted thiocarbonyl ylides of type 1. The fail ure of the competitive 1,5-dipolar electrocyclization is a result of the sterically unfavor able conformation 1a.

2

Stereokontrolowana polimeryzacja chiralnych monomerów heterocyklicznych

Duda A.

Polimery

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2004

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T. 49, nr 7-8

469-478

PL

W artykule przeglądowym obejmującym 80 odnośników literaturowych omówiono stereokontrolowane [stereoselektywną (chirogeniczną, prowadzącą do powstania racematu) i stereoelektywną (asymetryczną), prowadzącą do zróżnicowania enancjomerycznego)] polimeryzacje z otwarciem pierścienia chiralnych: oksiranów, tiiranów, laktonów, dilaktydów i N-karboksybezwodników alfa-aminokwasów. Przebieg powyższych enancjokontrolowanych polimeryzacji przeanalizowano w ujęciu kontroli przyłączenia cząsteczki monomeru zadanej przez konfigurację ostatniej jednostki monomerycznej w rosnącym łańcuchu lub przez konfigurację chiralnego ligandu w aktywnym centrum. Przedyskutowano także możliwość tworzenia uporządkowanych struktur wyższego rzędu przez powstałe na podstawie chiralnych monomerów heterocyklicznych izotaktyczne i czynne optycznie makrocząsteczki.

EN

A review with 80 references deals with stereoselective (race-mate-forming chirogenic) and stereoelective (asymmetric enantiomer-differentiating) ring-opening polymerizations of chiral oxiranes, thiiranes, lactones, dilactides, and N-carboxyanhydrides of alpha-aminoacids. These enantiocontrolled polymerizations are analyzed in terms of the chain-end control or site control mechanisms (CEM or SCM, respectively). Possibility of formation of highly ordered structures by the resulting izotactic and optically active macromolecules is also discussed.

3

Reaction of 2,2,4,4-Tetramethyl-3-thioxocyclobutanone with Dimethyl Diazomalonate Catalyzed by Rh2(OAc)4

Mlostoń G., Romański J., Heimgartner H.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 4

551-555

EN

The reaction of 2,2,4,4-tetramethyl-3-thioxocyclobutanone (1) with dimethyl diazomalonate in the presence of Rh2(OAc)4 in toluene at 50_C yielded a mixture of three products 10, 11, and 12. Thiocarbonyl ylide 8 is believed to be the common intermediate. The formation of 10 is rationalized by the 1,3-dipolar electrocyclization of 8 to give spirocyclic thiirane 9, which spontaneously eliminated sulfur. On the other hand, the 1,5- dipolar electrocyclization of 8 led to 1,3-oxathiole 11, which is converted into lactone 12 by hydrolysis.

4

Reactions of ethyl diazoacetate with thioketones

Kagi M., Mlostoń G., Heimgartner H.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 4

678-687

EN

The reaction of ethyl diazoacetate (10) with 9H-fluorene-9-thione (2a), thiobenzophenone (2b), and adamantanethione (2c), respectively, in THF yielded 1,3-dithiolane carboxylates (Scheme 2). Whereas in the first two cases the reaction proceeded at room temperature, heating to 60 degree C was necessary when the less reactive 2c was used. The additions with 2a and 2c occured in a regioselective way, yielding 1,3-dithiolane-2-carboxylate 11a and 1,3-dithiolane-4-carboxylate 12c, respectively, with opposite regiochemistry. On the other hand, a mixture of the two regioisomeric cycloadducts 11b and 12b was formed in the case of 2b. The analogous reaction of 10 with the sterically crowded thione 13 gave thiirane 14 as the sole product, and with the corresponding dithione 16, a mixture of the cis- and trans-dithiiranes 17 and 18 was formed (Scheme 3). Desulfurization with tris(dimethylamino)phosphine yielded the alpha, beta -unsaturated esters 15 and 19/20, respectively. The alpha, beta-insaturated ester 22 was the only product in the reaction of 10 with 9H-xanthene-9-thione (21), which had to be carried out at 60 degree C.