Metal‐free arylation of thiols with diaryliodonium salts has been developed. The application of a strong organic base enables the C−S bond formation under mild and experimentally simple conditions. The method allows for the synthesis of aryl sulfides containing a broad range of aryl groups from an array of thiols, including aryl, heteroaryl, and alkyl ones. The mechanism of the reaction was studied by DFT calculations, demonstrating that it proceeds via the inner sphere pathway involving formation of an Ar2I(SR) intermediate, followed by reductive elimination.
Alkynylation of aldehydes with alkynyl(aryl)iodonium salts catalyzed by an N-heterocyclic carbene (NHC) has been developed. The application of the organocatalyst and the hypervalent iodine group transfer reagent allowed for metal-free C−H functionalization and C−C bond formation. The reaction proceeds under mild conditions, at −40 °C and in the presence of an amine base, providing access to an array of heteroaryl-propargyl ketones containing various substituents in good to excellent yields. The mechanism of the reaction was investigated by means of both experiments and density functional theory calculations. 13 C-labeling and computations determined that the key alkynyl transfer step occurs via an unusual direct substitution at an acetylenic carbon, wherein an iodine-based leaving group is exchanged by a Breslow intermediate nucleophile. Moreover, kinetic studies revealed that the turnover-limiting step of the catalytic cycle is the generation of the Breslow intermediate, whereas the subsequent C−C bond formation is a fast process. These results are fully reproduced and rationalized by the calculated full free energy profile of the reaction, showing that the largest energy span is located between the protonated form of NHC catalyst and the transition state for the carbene attack on the aldehyde substrate.
Metal-free arylation of thiols with diaryliodonium salts has been developed. The application of a strong organic base ena-bles the C–S bond formation under mild and experimentally simple conditions. The method allows for the synthesis of aryl sulfides containing a broad range of aryl groups from an array of thiols, including aryl, heteroaryl, and alkyl ones. The mechanism of the reaction was studied by DFT calculations, demonstrating that is follows the inner sphere pathway involv-ing the incipient formation of Ar2I(SR) intermediate, followed by the reductive elimination.
Artykuł jest próbą wskazania właściwego podejścia do planowania zapasów. Wymaga to wła-ściwego doboru metody prognostycznej przez zharmonizowanie relacji między podażą a popytem. Proces powinien polegać na minimalizacji zapasów oraz ograniczeniu kosztów powiązanych z tym procesem. Pojęcia podaży i popytu są komplementarne i obustronnie się uzupełniają. Autorzy artykułu starali się poszukać odpowiedniej metody prognozowania. Dobór metody jest zależny od różnych aspektów i czynników zewnętrznych m.in. rodzaju popytu, dla którego tworzy się prognozę. W rzeczywistości logistycznej należy uwzględnić dwa rodzaje popytu -popyt zależny i niezależny. Popyt zależny definiowany jako popyt na dobra bądź usługi wywołany zapotrzebowaniem na inne produkty. Popyt niezależny, który jest rezultatem decyzji podjętych przez nabywców końcowych, wykształca się pod wpływem czynników systematycznych i losowych.Słowa kluczowe: planowanie zasobów, metody prognozowania popytu, logistyka, sieci handlowe
WprowadzeniePrognozowanie popytu we współczesnym biznesie ma kluczowe znaczenie dla dostawcy, producenta i sprzedawcy. Prognozy decydują o ilości towarów, które powinny być zakupione, produkowane i dostarczone. Prognozy kreują procesy i operacje z nimi związane. Dostarczenie produktu od producenta do klienta 1 andrzej_wojciechowski1@sggw.pl. 2 nat-89@wp.pl
Metal-free arylation of thiols with diaryliodonium salts has been developed. The application of a strong organic base ena-bles the C–S bond formation under mild and experimentally simple conditions. The method allows for the synthesis of aryl sulfides containing a broad range of aryl groups from an array of thiols, including aryl, heteroaryl, and alkyl ones. The mechanism of the reaction was studied by DFT calculations, demonstrating that is follows the inner sphere pathway involv-ing the incipient formation of Ar2I(SR) intermediate, followed by the reductive elimination.
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