Synthesis and conformational and configurational studies of diastereoisomeric <i>O</i>-protected 4-(arylsulfonimidoyl)butane-1,2,3-triols

J S W Kwong, M F Mahon, M D Lloyd, M D Threadgill

OAI: oai:purehost.bath.ac.uk:publications/86f1850a-dd37-4d3b-b464-7a3fdc02af0d • DOI: https://doi.org/10.1016/j.tet.2007.10.017

Chiral sulfoximines have applications as transition-state mimicking enzyme inhibitors, as peptide isosteres and as chiral auxiliaries in synthesis. To access the required O-protected 4- (arylsulfonimidoyl)butane-1,2,3-triols, 4S,5S-di(hydroxymethyl)-2,2-dimethyl-1,3-dioxolane (prepared from diethyl R,R-tartrate) was converted into its monobenzyl ether. Mitsunobu-like coupling with thiophenols gave 4S,5R-4-(benzyloxymethyl)-2,2-dimethyl-5-(arylthiomethyl)- 1,3-dioxolanes. Sulfoxidation and S-imination (trifluoroacetamide, iodosobenzene diacetate, rhodium acetate) proceeded without stereoselectivity, giving inseparable diastereomeric mixtures of 4S,5R,S(±)-4-(benzyloxymethyl)-2,2-dimethyl-5-(N-(trifluoroacetyl)arylsulfonimidoylmethyl)- 1,3-dioxolanes. Removal of the trifluoroacetyl protection allowed chromatographic separation of the diastereomeric 4S,5R,S(±)-4-(benzyloxymethyl)-2,2-dimethyl-5- (arylsulfonimidoylmethyl)-1,3-dioxolanes. The configurations at sulfur were determined by X-ray crystallography and some analysis of the solution and solid-state conformations was carried out. The resulting O-protected 4-(arylsulfonimidoyl)butane-1,2,3-triols are of use in developing enzyme inhibitors.

X-ray crystallography Sulfoximine Butanetriol Diastereoisomer conformation