A Convenient Synthetic Route towards 3, 5‐Bis(hydroxymethyl)pyrrolizidines: Stereoselective Synthesis of Unnatural (–)‐Hyacinthacine B2. Issue 14 (12th April 2019)

• Record Type: Journal Article
• Authors: Malatinský, Tomáš; Otočková, Barbora; Dikošová, Lívia; Fischer, Róbert
• Is Part Of: ChemistrySelect. Volume 4:Issue 14(2019)
• Page Start: 4233
• Page End: 4237
• Publication Date: 2019-04-12
• Subjects: Pyrrolizidines -- Hyacinthacines -- Nitrones -- Cycloaddition -- Diastereoselectivity; Chemistry -- Periodicals; 540.5
• DOI: 10.1002/slct.201900529
• Languages: English
• ISSNs: 2365-6549

Abstract

Abstract: A convenient synthetic route towards structurally intriguing hyacinthacines bearing an additional hydroxymethyl substituent at the C‐5 position is described. The strategy relies on syn ‐stereoselective 1, 3‐dipolar cycloaddition of D‐mannose‐derived nitrone, which provides the required stereochemistry at the A‐ring and at the bridgehead C‐7a carbon atom in target pyrrolizidines. Consecutive Horner‐Wadsworth‐Emmons olefination and intramolecular reductive amination cyclization are employed for the B‐ring construction with an emphasis on the stereochemistry of the newly formed stereocenter at C‐5. The simplicity of this method is exemplified by effective and highly stereocontrolled synthesis of the unnatural (–)‐enantiomer of hyacinthacine B2 . Abstract : A convenient synthetic route towards 3, 5‐bis(hydroxymethyl)pyrrolizidines, namely hyacinthacines, is described. The strategy relies on syn ‐stereoselective 1, 3‐dipolar cycloaddition of D‐ talo ‐configured nitrone, Horner‐Wadsworth‐Emmons olefination and intramolecular reductive amination cyclization. The simplicity of this method is exemplified by effective and highly stereocontrolled synthesis of unnatural (–)‐hyacinthacine B2 .