Ho, Joanne H HHodgson, RichardWagler, JorgMesserle, Barbara Ann2015-12-101477-9226http://hdl.handle.net/1885/59700A highly efficient rhodium(i) and iridium(i) catalysed dihydroalkoxylation reaction of alkyne diols is employed here for the synthesis of spiroketals and a fused bicyclic ketal. The two metal catalysts show differential selectivity and efficiency for either the cyclisation of the 5-exo or 6-endo-membered rings. For the first time, a dual metal (Rh and Ir) catalyst system is effectively utilised for the formation of the 5,6-spiroketals, more efficiently than the single metal catalysts. The two different metals create a dual activation pathway to enhance the 5- and 6-membered ring closure as compared with the equivalent single catalysts.Keywords: 6-membered rings; Catalyst system; Cyclisations; Dual activation; Metal catalyst; Single catalyst; Spiroketals; Acetylene; Catalysis; Catalyst selectivity; Iridium; Rhodium; Synthesis (chemical); Metals; alkyne; coordination compound; furan derivative; ir201010.1039/b926773e2016-02-24