Studies in the Synthesis of Coriolin. An Approach to a Functionalized BC Ring System

Article abstract of DOI:10.1021/jo00139a009

The conversion of methanoindene 8 into a highly functionalized intermediate that could be of use in a synthesis of coriolin (1) is described.The cyclopentenone 8 has been converted into the C ring of coriolin (1) with regiochemical and stereochemical control.Ozonolysis of the norbornenyl olefin and reductive workup gave 23, in which five of the eight assymetric centers are in the correct relative stereochemistry for eventual construction of coriolin (1).The differentiation of the primary hydroxymethyl groups in 23 was achieved by selective acylation with trimethylacetyl chloride (pivaloyl chloride).The structure of the major product of this reaction was proven to be 25 by X-ray crystallography.Studies of this acylation reaction were carried out on substrates having other functional groups attached to the C-1 hydroxy.A possible explanation of this somewhat surprising reactivity difference between the C-3 and C-8 hydroxymethyl groups is presented.