All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

  • 1
    ISSN: 1434-193X
    Keywords: Amino acids ; Spiro compounds ; Michael addition ; Copper reagents ; Curtius degradation ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Racemic spiropentylglycine (8) has been synthesized by sodium borohydride reduction of benzyl (E/Z)-2-chloro-2-spiropentylideneacetate (5-Bn), nucleophilic substitution of the chlorine in the product 6 with azide and hydrogenolytic deprotection of the resulting 7 (overall yield 15%). An alternative approach to 8 consisted of the coupling of the higher-order cuprate 10, generated by halogen-metal exchange from bromospiropentane (9), with the electrophilic glycine equivalent 11 followed by deprotection (overall yield 47%). Enantiomerically pure (1′-aminospiropentyl)acetic acid [(R)-16] (overall yield 16% from 5-Me) and 1-aminospiropentanecarboxylic acid [(R)-23] (29% from 5-Me) were obtained from the Michael adduct 14-Me of (4R,5S)-4,5-diphenyloxazolidin-2-one (13) and methyl (E/Z)-2-chloro-2-spiropentylideneacetate (5-Me). Racemic 1-aminospiropentanecarboxylic acid (R/S-23) was prepared by rhodium-catalyzed addition of dimethyl diazomalonate to methylenecyclopropane and subsequent Curtius degradation of the halfester 28 via the azide 29 (overall yield 14%). Upon standing in aqueous solution, 23 underwent complete rearrangement to the new 1-amino-2-methylenecyclobutanecarboxylic acid (24). The interesting derivative of azabicyclo[3.1.0]hexane-1-carboxylate 34 with an annelated spiropentane moiety and a β-amino acid fragment was incidentally obtained in a one-step intermolecular domino reaction starting with the addition of lithium benzylamide to methyl 2-chloro-2-cyclopropylideneacetate (32, 41% yield).
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...