Hydroxy-rhodium(I) catalyzed regioselective Michael addition of cyclic enones

An efficient protocol has been accomplished for the synthesis of cyclic α-enone adducts with 2mol% of Rh(I) catalyst. The key feature of this protocol is Rh-OH pre-catalyst performing the carbon–carbon bond formation α- to enone. Further, this method is extended to base-sensitive highly substituted enones and respective dimerized enone adducts are obtained in moderate to good yields. Hydroxy-rhodium catalyzed dimerization of various cyclic enones to the corresponding α-enone adducts is developed. The key feature of this method is that the base-sensitive, highly substituted enones also undergo dimerization and the resultant products are obtained in moderate to good yields.