Syntheses of disaccharide- and nucleoside-substituted cyclopentadienyl and indenyl ligands

This paper describes syntheses of new chiral cyclopentadienes and indenes derived from a disaccharide (trehalose) and a nucleoside (uridine). The reaction of lithium cyclopentadienide and indenide with a disaccharide, derived from trehalose, bearing methylated secondary hydroxyls and primary triflate groups, affords the trehalose bis-cyclopentadiene (5) and the trehalose bis-indene (6).These compounds have been fully characterized by NMR spectroscopy and the molecular structure of the trehalose bis-indene has been determined by X-ray diffraction. From uridine, a nucleoside in which secondary hydroxyls have been protected with isopropylidene groups and the free primary hydroxyl function transformed into the tosylate derivative, the reaction with lithium cyclopentadienide or lithium indenide under sonication conditions leads to either uridine cyclopentadiene (9) or uridine indene (10). The molybdenum(II) complex 7 has been obtained from trehalose bis-cyclopentadiene and its molecular structure determined by X-ray diffraction. From the uridine cyclopentadiene the molybdenum(II) complex 11 has been prepared and characterized.