Work

One-Pot Stereoselective Synthesis of the Naphthofurano-Iminosugars via a [3 + 2] Cycloaddition Reaction

Year: 2024

Type: article

Abstract: Described here is the synthesis of novel naphthofurano-iminosugars (4) using 2,3-O-isopropylidene D-ribose tosylate (1a), anilines (2), and 1,4-benzoquinone (3a) as starting materials through the key iminium-ion/enamine intermediates by [3+2] cyclization reactions at room temperature. The reaction has unique regioselectivity and stereoselectivity with moderate to excellent yields. The adaptability of this method has been demonstrated by a variety of substituted anilines on which both electron-donating and electron-withdrawing were employed in the reactions well. Notably, the treatment of the fused multicyclic iminosugar 4 with TFA efficiently leads to an inter-esting unexpected pyridinium salt (8) possible via four steps in sequence: deprotection of 2,3-O-isopropylidene group, furan ring open-ing, intramolecular elimination of water, and dehydration condensation of OH groups.

Source: The Journal of Organic Chemistry

DOI: 10.1021/acs.joc.4c01360