Synthesis and Applications of Bis-azolium and Bis-azolene Derivatives

The thesis deals two main aspects of pre bis-N-hetero cyclic carbene (NHC) towards organocatalyst and ancillary ligands for organometallic compounds (Chart A). New Trӧger’s base bridged diimidazolium salts were synthesized and characterized. Subsequently, these heterocyclic ring systems, (+_))methanodibenzo diazocine imidazolium/benzimid-bis-azolium salts, were employed as organocatalysts in ‘carboncarbon’bond formation reactions such as Benzoin condensation and dimerization of cyclohexen-1-one to Baylis Hillman type product. A new easy and metal free synthetic\ud methodology was developed for the synthesis of 1,2-diferrocenylethanedione from ferrocenealdehyde using (_+)methanodibenzo diazocine imidazolene as a catalyst followed by silica-gel oxidation. Synthetically challenging rigid C2-symmetrical 4,10-and 2,8- diimidazo-methano dibenzo diazocines were synthesized and readily converted to diazolium salts from selective alkylation