Mannich Reactions of Carbohydrate Derivatives with Ketones To Afford Polyoxy-Functionalized Piperidines
作者:Lingaiah Maram、Fujie Tanaka
DOI:10.1021/acs.orglett.9b00105
日期:2019.2.15
Mannich reactions of carbohydrate derivatives with ketones that afford polyoxy-functionalized piperidines are reported. Ketone nucleophiles (enamines/enolates) were generated in the presence of the amines used for the formation of the iminium ions of sugar derivatives with or without an additive. Conditions to preferentially generate piperidine derivatives rather than tetrahydrofurans were identified
An effective and facile method for the synthesis of N-substituted trihydroxypiperidine derivatives is described. The Mannich-type reaction of protected 5-O-tosylate pentoses with amines and ketones in the presence of p-TsOH provides convenient access to the stereoselective synthesis of N-substituted iminosugar C-glycosides as potential glucosidase inhibitors in good to excellent yields.
An efficient one-pot method for the stereoselectivesynthesis 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
Switching Electrophile Intermediates to Nucleophiles: Michael and Oxa-Diels–Alder Reactions to Afford Polyoxy-Functionalized Piperidine Derivatives with Tetrasubstituted Carbon
作者:Lingaiah Maram、Fujie Tanaka
DOI:10.1021/acs.orglett.0c00735
日期:2020.4.3
Michael, Michael-annulation, and oxa-Diels–Alder reactions of carbohydrate derivatives that afford polyoxy-functionalized piperidine derivatives bearing tetrasubstituted carbon at the 3-position of the piperidine ring are reported. Iminium ions generated from carbohydrate derivatives with amines were converted to enamines in situ, which acted as nucleophiles. As a result, substituents were introduced at
and efficient one‐pot method has been developed for the stereoselective synthesis of structurally diverse novel iminosugarC‐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