Dimethyl octamethyltricyclo[4.2.2.02,5] deca-3,759-triene-7,8-dicarboxylate (Cookson's diester) revisited: Cope rearrangement and epoxidation site selectivity

Article abstract of DOI:10.1016/S0040-4039(00)79969-2

Dimethyl octamethyltricyclo[4.2.2.0^2,5]deca-3,7,9-triene-7,8-dicarboxylate (Cookson's diester) (8) is rearranged thermally via a double Cope reaction to its ring-degenerate isomer (14). The structure of diester (8) (indirectly) and the rearrangement product (14) (directly) are placed on an unequivocal base by X-Ray structure analysis. AMI semi-empirical calculations support the preferential formation of (8) from the reaction of DMAD with transient intermediate diene (7). Epoxidation studies (mCPBA) have been conducted and firm site selectivities determined. A correction is made to an earlier report on the epoxidation selectivity of (18).