2‐Isocyanato‐2‐alkenoates–Synthesis and Reactions

Effenberger, Franz; Baumgartner, Christian; Kühlwein, Jürgen

doi:10.1002/anie.198910531

Cited by 6 publications

(1 citation statement)

References 9 publications

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“…The synthesis of the azaspirene analogue 6a is shown in Scheme 3. Isocyanate 8 42 was obtained from commercially available α-acetamidocinnamic acid (9) by the following transformation sequence: esterification of 9, replacement of the N-Ac group with the N-Boc group giving 12, 43 and isocyanate formation by using Kokotos protocol 44 to afford 8 in good yields (Scheme 3A). Furan 18 was prepared by the following six-step sequence: Claisen condensation between 3pentanone (13) and benzyloxyacetyl chloride (14), removal of the Bn group, and spontaneous cyclization to afford furanone 7 in excellent yield (Scheme 3B).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Elucidation of Racemization Process of Azaspirene Skeleton in Neutral Aqueous Media

et al. 2018

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Azaspirene and related congeners, which possess various biological activities, have a unique spirocyclic core structure. However, there are few studies on the chemical properties of (−)-azaspirene, despite the fact that it may provide important insights into unveiling the biosynthetic pathway. Here, we report a nine-step chemical synthesis of an azaspirene analogue with a new finding that the natural (−)-azaspirene skeleton easily racemizes in neutral aqueous media.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Elucidation of Racemization Process of Azaspirene Skeleton in Neutral Aqueous Media

et al. 2018

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Aminosäuren, 18. Darstellung und Reaktionen von 2‐Isocyanato‐2‐alkensäureestern

1994

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Amino Acids, 1 8 1 ' 1 . -Preparation and Reactions of 2-Isocyanato-2-alkenoates 2-Isocyanato-2-alkenoates 3 were obtained in good yields by the perrhenate-catalyzed decomposition of 2-azidoalkanoates 1 in the presence of diphosgene (2a) or phosgene (2b). Methyl 2-azidopropionate (lh) reacts to give a mixture of methyl 2-isocyanato-2-propenoate (3h) and methyl 2-chloro-2-isocyanatopropionate (4). The addition product 4 could easily be converted into 3h by elimination of HC1 with triethylamine at 0°C. With benzyl alcohol (5a) and tert-butyl alcohol (5b) the isocyanates 3 react smoothly to give the corresponding Z-or Boc-protected 2,3-didehydroamino acid esters 6 and 7 , respectively. The acrylic acid derivative 3h reacts as dienophile with various dienes to yield the Diels-Alder adducts 8-10.

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