One-pot access to 2-amino-3-arylbenzofurans: direct entry to polyheterocyclic chemical space.

As a means to make new benzofuran-embedded polycyclic structures, we established two efficient one-pot sequential coupling routes to 2-amino-3-arylbenzofurans and 2-amino-3-arylnaphtho[2,1-b]furans. Further ring formation (six- and seven-membered rings) with the resulting amine moiety at the C2 position of benzofurans was realized, leading to further expansion of benzofuran-based chemical space.

One-Pot, Three-Component Approach to Diarylmethylphosphonates: A Direct Entry to Polycyclic Aromatic Systems.

A new type of three-component reaction was developed consisting of aldehydes, electron-rich (hetero)arenes, and trialkyl phosphite, which provided facile access to a wide range of diarylmethylphosphonates under mild reaction conditions. Simple one- or two-step synthetic manipulation of the resulting compounds enabled us to reach several polycyclic (hetero)aromatic systems efficiently.

One-Pot Synthesis of Structurally Diverse Iminosugar-Based Hybrid Molecules.

A one-pot iminium-ion-based strategy has been developed for the synthesis of structurally novel iminosugar-based hybrid molecules. Iminium ion derived from l-rhamnose lactol-mesylate reacted with electron-rich aromatic systems in an inter/intra molecular fashion to furnish pyrrolidine-based iminosugar C-aryl glycosides with a high degree of stereoselectivity. Iminium ion also reacted readily with active methylene compounds such as 4-hydroxycoumarin, 4-hydroxyquinolinone, and lawsone to provide iminosugar C-coumarin/quinolinone/naphthoquinonyl glycosides in very good yields. Azomethine ylide generated from an iminium ion derivative underwent dipolar cycloaddition reaction with 1,4-quinones to furnish novel isopyrrolonaphtho/anthroquinon-based iminosugar-hybrids. The preliminary cytotoxic activities of some of the synthesized iminosugar-hybrids have been assayed against various human cancer cell lines and some of the hybrid molecules exhibited promising anticancer activities.

Iminosugar C-Nitromethyl Glycoside: Stereoselective Synthesis of Isoxazoline and Isoxazole-Fused Bicyclic Iminosugars.

A simple and efficient method for the stereoselective synthesis of isoxazoline/isoxazole-fused iminosugar derivatives has been developed using intramolecular nitrile oxide cycloaddition (INOC) as a key step. Iminosugar C-nitromethyl glycosides, derived from simple carbohydrates, served as excellent nitrile oxide precursors in 1,3-dipolar cycloaddition reactions. N-Alkenyl iminosugar C-nitromethyl glycosides afforded novel isoxazoline-fused indolizidine-, pyrrolizidine-, and quinolizidine-based iminosugars in excellent yields with a high degree of stereoselectivity, whereas N-alkynyl iminosugar C-nitromethyl glycosides furnished the corresponding isoxazole containing tricyclic iminosugars in very good yields.

Iminosugar C-Nitromethyl Glycosides and Divergent Synthesis of Bicyclic Iminosugars.

An efficient one-pot method for the stereoselective synthesis of novel iminosugar C-nitromethyl glycosides is described. This new class of iminosugar glycosides has versatile nitromethyl functionality whose utility was further demonstrated in the single-step synthesis of bicyclic iminosugars. Under reagent-free conditions, the N-allyl-C-nitromethyl glycosides resulted in intramolecular cyclization to iminosugar-oximes, whereas under SET oxidation, they furnished cyclopropane-fused iminosugars. The N-propargyl-C-nitromethyl glycosides underwent an unprecedented ketenimine-acrylamidine-Michael addition cascade reaction to give bicyclic amidines.

One-Pot Synthesis of Hydrophobically Modified Iminosugar C-Alkynylglycosides: Facile Synthesis of Polyhydroxy Tetrahydroindolizines.

A mild and efficient one-pot method has been developed for the stereoselective synthesis of structurally diverse novel iminosugar C-alkynylglycosides. The generality of this methodology has been demonstrated with a wide variety of amines and copper acetylides. This one-pot method has been exploited in the synthesis of new class of DNA cross-linking agents, polyhydroxy 1-vinyl-tetrahydroindolizine derivatives.

A diversity oriented one-pot synthesis of novel iminosugar C-glycosides.

A mild and highly efficient one-pot method has been developed for the stereoselective synthesis of structurally diverse novel iminosugar C-aryl glycosides. The generality of this methodology is demonstrated with a wide variety of aryl nucleophiles and amines. The synthetic potential of this methodology is further shown in the domino synthesis of iminosugar based hybrid molecules.