Stereocontrolled synthesis of spiroketals via a remarkable methanol-induced kinetic spirocyclization reaction Journal Article

  


Authors: Potuzak, J. S.; Moilanen, S. B.; Tan, D. S.
Article Title: Stereocontrolled synthesis of spiroketals via a remarkable methanol-induced kinetic spirocyclization reaction
Abstract: A methanol-induced kinetic spiroketalization reaction has been developed for the stereocontrolled target- and diversity-oriented synthesis of spiroketals. In contrast to existing methods for spiroketal synthesis, this reaction does not depend on thermodynamic product stability or require axial attack of an oxygen nucleophile. Stereodiverse glycals are alkylated at the C1 position with side chains bearing protected hydroxyl groups. After alcohol deprotection, the glycal is epoxidized stereoselectively, then the side chain hydroxyl is spirocyclized with inversion of configuration at the anomeric carbon by addition of excess MeOH at -63 °C. This spirocyclization reaction appears to proceed by MeOH hydrogen-bonding catalysis and has been used to form five- and six-membered rings with stereoisomeric substituents. In some cases, the stereocomplementary spiroketals can be also obtained by classical acid-catalyzed equilibration. Copyright © 2005 American Chemical Society.
Keywords: unclassified drug; kinetics; glycosylation; temperature; thermodynamics; cyclization; nuclear magnetic resonance; acetal derivative; molecular conformation; synthesis; stereochemistry; stereoisomerism; spiro compound; spiroketal; spiro compounds; diastereoisomer; methanol; glycoside; enantioselectivity; epoxide; epoxidation; entropy; suzuki reaction; spirocyclization reaction
Journal Title: Journal of the American Chemical Society
Volume: 127
Issue: 40
ISSN: 0002-7863
Publisher: American Chemical Society  
Date Published: 2005-10-12
Start Page: 13796
End Page: 13797
Language: English
DOI: 10.1021/ja055033z
PUBMED: 16201793
PROVIDER: scopus
DOI/URL:

http://www.scopus.com/inward/record.url?eid=2-s2.0-26444612098&partnerID=40&md5=16562c2f69e6195c3590ddbf29fe0e3e
Notes: --- - "Cited By (since 1996): 31" - "Export Date: 24 October 2012" - "CODEN: JACSA" - "Source: Scopus"
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MSK Authors
  1. Derek S Tan
    92 Tan
  2. Sirkka Moilanen
    5 Moilanen
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