Abstract

Iodo-(5,10,15,20-tetrakis(1,2,3,4,5,6,7,8-octahydro-1,4:5,8-dimethanoanthracen-9-yl)porphyrinatorhodium(III), designated as [Rh(P*)(I)], was prepared and its catalytic activity in the asymmetric cyclopropanation of alkenes with ethyl diazoacetate (EDA) was examined. High catalyst turnovers (TON >10 3) and moderate enantioselectivities (up to 68% ee) were observed. However, the obtained trans/ cis ratios are low. Competition experiments revealed that electron-donating substituents on styrene accelerate the cyclopropanations. The log( k X/ k H) versus σ + plot for substituted styrenes exhibits a good linearity with a small negative ρ + value (−0.14). [Rh(P*)(I)] is also active in the intramolecular cyclopropanation of allyl diazoacetates. A comparison between rhodium and ruthenium porphyrin complexes was made.

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