The key reaction in this approach to C-glycosphingolipids is the stereoselective iodocyclization of a sugar-linked homoallylic carbonimidothioate. E and Z reaction substrates were assembled in a convergent fashion via an alkene metathesis strategy and exhibited the same alkene facial selectivity in the iodocyclization irrespective of alkene geometry, although the E alkene was found to be less reactive.
Ahmad Altiti and David Mootoo, Org. Lett., 2014, 16 (5), pp 1466–1469. DOI: 10.1021/ol5002686