19190-95-5Relevant academic research and scientific papers
One-pot synthesis of oxazolidinones and five-membered cyclic carbonates from epoxides and chlorosulfonyl isocyanate: Theoretical evidence for an asynchronous concerted pathway
Demir, Esra,Sari, Ozlem,?etinkaya, Yasin,Atmaca, Ufuk,Erdem, Safiye Sa?,?elik, Murat
, p. 1805 - 1819 (2020/11/07)
The one-pot reaction of chlorosulfonyl isocyanate (CSI) with epoxides having phenyl, benzyl and fused cyclic alkyl groups in different solvents under mild reaction conditions without additives and catalysts was studied. Oxazolidinones and five-membered cyclic carbonates were obtained in ratios close to 1:1 in the cyclization reactions. The best yields of these compounds were obtained in dichloromethane (DCM). Together with 16 known compounds, two novel oxazolidinone derivatives and two novel cyclic carbonates were synthesized with an efficient and straightforward method. Compared to the existing methods, the synthetic approach presented here provides the following distinct advantageous: being a one-pot reaction with metal-free reagent, having shorter reaction times, good yields and a very simple purification method. Moreover, using the density functional theory (DFT) method at the M06-2X/6-31+G(d,p) level of theory the mechanism of the cycloaddition reactions has been elucidated. The further investigation of the potential energy surfaces associated with two possible channels leading to oxazolidinones and five-membered cyclic carbonates disclosed that the cycloaddition reaction proceeds via an asynchronous concerted mechanism in gas phase and in DCM.
Alkene Syn- And Anti-Oxyamination with Malonoyl Peroxides
Curle, Jonathan M.,Perieteanu, Marina C.,Humphreys, Philip G.,Kennedy, Alan R.,Tomkinson, Nicholas C. O.
supporting information, p. 1659 - 1664 (2020/02/13)
Malonoyl peroxide 6 is an effective reagent for the syn- or anti-oxyamination of alkenes. Reaction of 6 and an alkene in the presence of O-tert-butyl-N-tosylcarbamate (R3 = CO2 tBu) leads to the anti-oxyaminated product in up to 99% yield. Use of O-methyl-N-tosyl carbamate (R3 = CO2Me) as the nitrogen nucleophile followed by treatment of the product with trifluoroacetic acid leads to the syn-oxyaminated product in up to 77% yield. Mechanisms consistent with the observed selectivities are proposed.
Synthesis and configurational assignment of the amino alcohol in the eastern fragment of the GE2270 antibiotics by regio- and stereoselective addition of 2-metalated 4-bromothiazoles to α-chiral electrophiles
Delgado, Oscar,Heckmann, Golo,Mueller, H. Martin,Bach, Thorsten
, p. 4599 - 4608 (2007/10/03)
A synthesis of the eastern fragment of the thiazole peptide GE2270 A (1) has been developed. The synthetic approach relies on the regioselective functionalization of 2,4-dibromothiazole (5) via metalation and nucleophilic addition (at C2) or palladium-mediated cross-coupling (at C2 or C4). The stereochemistry at the N-bearing stereocenter was established by coupling of 2-metalated 4-bromothiazoles (4) to enantiomerically pure mandelic acid derivatives. Both the erythro (2) and threo (3) configurated amino alcohols were prepared with high diastereoselectivities depending on the electrophile employed. More specifically, the threo-configurated (S,R)-4-bromothiazolyl β-amino alcohol 6 was synthesized from O-TBS protected (R)-mandelonitrile in 62% yield. Its N-PMB protected (R,S)-enantiomer 20 was obtained from O-TBS protected (S)-mandelic aldehyde in 67% yield. The eryrthro-configurated (S,S)-4-bromothiazolyl β-amino alcohol 29 was prepared from O-TBS protected (S)-ethyl mandelate in four steps and 33% overall yield. The bithiazole moiety in the desired products 2 and 3 was finally established by the regioselective Negishi coupling of 2,4-dibromothiazole (5) and the 4-zincated, N-Boc protected thiazole derivatives of the diastereomeric 4-bromothiazolyl β-amino alcohols 6 and 29.
Catalytic additions of acylsilanes to imines: An acyl anion strategy for the direct synthesis of α-amino ketones
Mattson, Anita E.,Scheidt, Karl A.
, p. 4363 - 4366 (2007/10/03)
(Chemical Equation Presented) The addition of acylsilanes to imines catalyzed by neutral carbenes (or zwitterions) generated in situ from readily available thiazolium salts is described. The general reaction successfully utilizes acylsilanes as carbonyl anion precursors and is tolerant of a range of structural diversity on the acylsilane or imine electrophile. The overall reaction utilizes easily available precursors and directly accesses protected α-amino ketones in the correct oxidation state.
The Reaction of Chlorosulfonyl Isocyanate with Epoxides. A Novel Conversion of Epoxides to Cyclic Carbonates
Keshava Murthy, K. S.,Dhar, D. N.
, p. 1721 - 1725 (2007/10/02)
The facile reaction of chlorosulfonyl isocyanate (CSI) with epoxides is described.The initially formed 2-chlorosulfonylimino-1,3-dioxolane 2a-e and N-chlorosulfonyl-1,3-oxazolidin-2-one 3a-e derivatives undergo smooth hydrolysis to yield the corresponding 1,3-dioxolan-2-one 4a-e and 1,3-oxazolidin-2-one 5a-e derivatives respectively.This reaction sequence provides a convenient one-pot method for the conversion of epoxides to cylic carbonates.Substrates such as 1g-i are exceptions to this otherwise general reaction pathway.
A CONVENIENT ONE-POT SYNTHESIS OF 1,3-DIOXOLAN-2-ONES FROM EPOXIDES USING CHLOROSULFONYL ISOCYANATE
Murthy, K. S. Keshava,Dhar, D. N.
, p. 687 - 696 (2007/10/02)
An efficient, simple and stereospecific one-pot method is described for the conversion of epoxides to 1,3-dioxolan-2-ones, by using chlorosulfonyl isocyanate (CSI).
