Efficient Cycloisomerization of Propargyl Amides by Electrophilic Gold(I) Complexes of KITPHOS Monophosphines: A Comparative Study
journal contributionposted on 27.09.2010, 00:00 by Simon Doherty, Julian G. Knight, A. Stephen K. Hashmi, Catherine H. Smyth, Nicholas A. B. Ward, Katharine J. Robson, Sophie Tweedley, Ross W. Harrington, William Clegg
Electrophilic gold(I) complexes of diphenyl- and dicyclohexylphosphino-based KITPHOS monophosphines catalyze the 5-exo-dig cycloisomerization of a range of propargyl amides to afford the corresponding alkylidene oxazolines; in all cases catalysts formed from diphenylphosphino-substituted KITPHOS monophosphines outperformed their dicyclohexylphosphino counterparts as well as that based on triphenylphosphine, an indication that the biaryl/biaryl-like framework may be responsible for imparting high catalyst efficiency.