Stereocontrolled synthesis of spiroketals via Ti(Oi-Pr)4- mediated kinetic spirocyclization of glycal epoxides with retention of configuration Journal Article
| Authors: | Moilanen, S. B.; Potuzak, J. S.; Tan, D. S. |
| Article Title: | Stereocontrolled synthesis of spiroketals via Ti(Oi-Pr)4- mediated kinetic spirocyclization of glycal epoxides with retention of configuration |
| Abstract: | A Ti(Oi-Pr)4-mediated kinetic spiroketalization reaction has been developed for the stereocontrolled target- and diversity-oriented synthesis of spiroketals. In contrast to most existing methods for spiroketal synthesis, this reaction does not rely upon thermodynamic controlover the stereochemical configuration at the anomeric carbon. Stereochemically diverse glycals are first alkylated at the C1-position to introduce a hydroxyl-bearing side chain, then epoxidized stereoselectively. Treatment with Ti(Oi-Pr)4 leads to an unusual kinetic epoxide-opening spirocyclization (spirocycloisomerization) with retention of configuration at the anomeric carbon. The reaction is proposed to proceed via a chelation-controlled mechanism and has been used to form five-, six-, and seven-membered rings with stereochemically diverse substituents. This approach may also be useful for the related intermolecular β-mannosidation reaction. This Ti(Oi-Pr)4-mediated spirocyclization is stereochemically complementary to our previously reported MeOH-induced spirocyclization, which proceeds with inversion of configuration, and together, these reactions provide comprehensive access to systematically stereochemically diversified spiroketals. Copyright © 2006 American Chemical Society. |
| Keywords: | unclassified drug; kinetics; conformation; cyclization; acetal derivative; synthesis; metal; chelation; stereochemistry; stereoisomerism; spiro compound; spiro compounds; titanium derivative; titanium; glycosides; epoxy compounds; methanol; carbohydrate conformation; chemical reaction kinetics; epoxide; epoxidation; glycal epoxide; spiroketal derivative; hexoses |
| Journal Title: | Journal of the American Chemical Society |
| Volume: | 128 |
| Issue: | 6 |
| ISSN: | 0002-7863 |
| Publisher: | American Chemical Society |
| Date Published: | 2006-02-15 |
| Start Page: | 1792 |
| End Page: | 1793 |
| Language: | English |
| DOI: | 10.1021/ja057908f |
| PUBMED: | 16464069 |
| PROVIDER: | scopus |
| PMCID: | PMC2553756 |
| DOI/URL: | |
| Notes: | --- - "Cited By (since 1996): 26" - "Export Date: 4 June 2012" - "CODEN: JACSA" - "Source: Scopus" |
Altmetric
Citation Impact
BMJ Impact Analytics
Related MSK Work