Total synthesis of a protected form of sphingofungin E using the [3,3]-sigmatropic rearrangement of an allylic thiocyanate as the key reaction.
An approach to the stereocontrolled synthesis of the protected form of sphingofungin E (32) starting from the known protected d-glucose derivative 3 is described herein. For the construction of a tetrasubstituted carbon atom that is substituted with nitrogen, the [3,3]-sigmatropic rearrangement of thiocyanate 8 was employed. Subsequent functional group interconversions afforded the highly functionalized fragment, allylic bromide 26. Its coupling reaction with the known C(12) hydrophobic segment 2, followed by further manipulation, completed the total synthesis.
Creation of quarternary stereocentres via [3,3]-sigmatropic rearrangement of allylic thiocyanates. A synthetic approach to (+)-myriocin
Abstract A stereoselective approach to the advanced precursor of (+)-myriocin, 3-deoxy-1,2:5,6-di- O -isopropylidene-3-methoxycarbonylamino-α- d -glucofuranose 3- C -carboxylic acid, via the [3,3]-sigmatropic rearrangement of allylic thiocyanates prepared from d -glucose is presented. From the observed results, supported by DFT calculations, we can conclude that the [3,3]-sigmatropic rearrangement of the thiocyanato group in allylic hexofuranosides is strongly influenced by the steric interaction of the 1,2- O -isopropylidene group in the transition states.
RDF Keyword Search based on Keywords-To-SPARQL Translation
In this paper, we present a summary of our work on RDF keyword search. Given a set of keywords, our method automatically generates a set of candidate SPARQL queries, and their natural language description, to be evaluated on the RDF data graph. We discuss our approach, highlighting current and future directions.