Platinum(II) Catalyzed Enantioselective Cycloisomerizations of 3‐Hydroxylated 1, 5‐Enynes. Issue 7 (25th March 2013) - Zhang, Yang
Abstract The enantioselective cycloisomerization of 3‐hydroxylated 1, 5‐enynes into bicyclo[3.1.0]hexanones was investigated by using cyclometalated NHC‐platinum phosphoramidite complexes as pre‐catalysts. Several new complexes were prepared. They generate cationic, electrophilic PtII species that efficiently promote the cycloisomerization process. Enantiomeric excesses up to 81 % were obtained in the reactions of enynes with aryl‐substituted alkyne functions (8 examples, 70–81 % ee).