An atom-economic and diazo-free strategy for the construction of novel pseudo anomeric C-1 alkenyl spirocyclopropyl sugars is described. Leveraging the 1,2-migration pathway of propargyl esters under gold(I) catalysis, easily available exo-glycals undergo β-selective alkenylcarbenoid insertion in moderate to excellent yields. Preferential activation of propargyl moieties and concerted [2 + 1] insertion are both favored through ligand choice and electron enrichment of esters. Stereocontrol using conformational bias and rearrangement are also demonstrated.
Gold(I)-Catalyzed Reactions of exo-Glycals with Propargyl Esters toward C-1 Alkenyl Spirocyclopropyl Carbohydrates
M. Lang, S. Walter, D. Hatey, A. Blanc, P. Compain, and N. Kern
Org. Lett. 2024, 26, 38, 8017-8022, DOI : https://doi.org/10.1021/acs.orglett.4c02754
A. Blanc, équipe COSyS, Institut de Chimie de Strasbourg (UMR 7177).