The stereochemistry of organometallic compounds. Part II. Effects of non-bonded substituents on the cis–trans-equilibrium ratios of tricarbonyl(indane)chromiums

Abstract

A series of 1- and 2-substituted indanes have been treated with hexacarbonylchormium in three solvents : diglyme, decalin, and cyclohexanol. The ratios of cis- to trans-tricarbonyl(indane)chromiums thus obtained have been shown to be thermodynamically controlled, as individual isomers come to equilibrium under the conditions used. The ratio are discussed in terms of non-bonded interactions between the substituent and the chromium carbonyl group. Some unusual cases of preferred stabilisation of cis-isomers have been found.