STERICALLY CROWDED CYCLOPROPANATION CATALYSTS. SYN-SELECTIVITY USING RHODIUM(III)PORPHYRINS

Article abstract of DOI:10.1016/0040-4020(82)87014-2

Rhodium(III)porphyrins catalyze the decomposition of ethyl diazoacetate and the transfer of ethoxycarbonylcarbene to alkenes to form cyclopropanes in moderate to high yields.When compared with other catalysts a large syn-selectivity was observed on reaction with cis-alkenes.This selectivity increased with the size of the substituents, and suggested a preferencial direction of approach of the alkene towards a rhodium-carbene complex.