A variety of Rh(II) catalysts were screened for enantioselectivity in the cyclopropanation of styrene with alpha-nitro-alpha-diazo carbonyl compounds and found to give modest to high yields in a wide range of solvents but modest enantioselectivities (up to 41% e.e. for substrate 9c). Copper catalysts with bis(oxazoline) ligands gave higher enantioselection, with e.e. up to 72% for the major diastereoisomer and yields up to 55%. The use of ethyl diazoacetate as an additive was necessary to obtain improved yields. The first example of intramolecular cyclopropanation involving alpha-nitro-alpha-diazo carbonyls is also reported. Rh(II) carboxylate 4b catalysed the formation of 9-membered nitro cyclopropyl lactones giving up to 66% yield and 61% e.e. (C) 2002 Elsevier Science B.V. All rights reserved.