Palladium-Catalyzed Double Allylation of Sugar-Imines by Employing Tamaru–Kimura’s Protocol: Access to Unnatural Iminosugars

Abstract

Conversion of vinyl pyranosylamine and vinyl furanosylamines to 2,6- and 2,5-disubstituted pyrrolidine and piperidine iminosugars, respectively, in one pot was developed using Kimura and Tamaru's procedure, where a Pd salt in the presence of EtZn was used for the domino reaction. In this procedure, double allylation, which involves nucleophilic allylation-heterocyclization, took place to give desired nitrogen heterocycles. This strategy was further elaborated to synthesize some unnatural deoxycalystegines, hydroxylated pyrrolidines, piperidines, and indolizidine analogues.

Synthetic Entry to the 2-Azatricyclo[4.3.2.04,9]undecane Ring System via Tropone

“…The olefin could also be cleanly hydrogenated to give 40 . In addition, dihydroxylation of the olefin delivered diol 41 , the stereochemistry of which was assigned based on nuclear Overhauser effect (nOe) experiments. The ketone of 14a could be reduced to give the alcohol 42 as a single diastereomer.…”

Glycoside Mimics from Glycosylamines: Recent Progress

“…In very recent work, Rao et al reported an interesting Pd-mediated double allylation process in which the C-N bond is created in the same step as the C-C bond [74]. This procedure requires a substrate (furanosyl- or pyranosylamine) carrying a vinyl group at C-4 or C-5, respectively.…”