Efficient one-pot synthesis of the unexpected fused multicyclic iminosugars by an aza-Diels–Alder mechanism

Abstract

A simple and efficient one-pot synthesis has been developed for the first time by an aza-Diels-Alder mechanism for the stereoselective synthesis of novel fused multicyclic iminosugars with structural diversity. The...

One-Pot Stereoselective Synthesis of Furantetrahydroquinoline Derivatives Using d/l-Ribose with a 2,3-O-Isopropylidene Group

“…Finally, density functional theory (DFT) computations (by using Gaussian 09 software, Rev. B.01) further suggested the aza-Diels–Alder reaction of A and D (current work) rather than the reaction of C′ and D (similar to the previous work), where the former has obvious thermodynamic advantages (see the Supporting Information).…”

“…Recently, our group developed an effective protocol for furnishing a series of novel unexpected fused multicyclic iminosugars using various aniline and tosylated D-ribose as starting materials. 16 The reactions were catalyzed by Yb(OTf) 3 in the mixed solvents of toluene and methanol at a temperature of 80 °C. In this work, the reaction of D-ribose with 2,3-Oisopropylidene group and aniline was initially carried out following the same conditions.…”

“…However, the installation and removal of specific protective groups still limit the synthetic chemistry of carbohydrates, and more efficient and simple synthetic protocols with the minimal protecting groups need to be developed for carbohydrate research. As a continuation of our studies on the fused multicyclic sugar, herein, we would like to report the synthesis of a series of THQ-fused carbohydrate derivatives by a one-pot Yb­(OTf) 3 -catalyzed aza-Diels–Alder reaction of d / l -ribose with a 2,3- O -isopropylidene group and different anilines (Scheme d). The inactive sugars were successfully adopted into the synthesis of such furantetrahydroquinolines.…”

One‐Pot Stereoselective Synthesis of Different Fused Multicyclic Iminosugars Based on the Iminium‐Ion Intermediate

“…[ 12 ] When aromatic amines were employed in the reaction, the fused multicyclic iminosugars (Scheme 1c) were conveniently obtained in good yields in our group. [ 13 ] The plausible mechanism of the reaction was aza‐Diels‐Alder cycloaddition (Povarov reaction) [ 14 ] using iminium‐ion A as diene and its isomer enamine B as dienophile. Such tautomerism between imine and enamine was also observed in Fujie Tanaka's research.…”

Lewis Acid-Promoted Oxidative Cleavage of Carbon–Carbon Bonds: Synthesis of N-Arylated Lactam-Type Iminosugars

“…In our efforts on the search for the potent iminosugar-based glycosidase inhibitors, several simple synthetic methodologies were developed for preparing the fused multicyclic iminosugars from D-ribose tosylate and aniline through the iminium ion A and its tautomer enamine B (Scheme 1d). 13 Reduction of A could easily give N-arylated iminosugars 2, which together with other N-arylated lactam-type iminosugars 5 were effective immunosuppressive reagents. 14 However, iminosugar 2 could slowly auto-oxidize into bis-carbonyl compound 3 in air, and occasionally, the reaction of D-ribose tosylate and aniline with the aid of Sc(OTf) 3 could directly afford compound 3 in low yield.…”