Direct observation of the effect of transannular interaction on the single bond lengths of tricyclo[2.1.0.02,5]pentane derivatives

Abstract

X-Ray structure analysis of 1′,5′-bis(acetoxymethyl)spiro(1,3-dioxolane-2,3′-tricyclo[2.1.0.0^2,5]pentane)(1) reveals that the bond distance (1.455 Å) between the bridgehead carbon atoms is elongated in comparison with the same bond in the ketone 1,5-bis(acetoxymethyl)tricyclo[2.1.0.0^2,5]pentan-3-one (2), thereby providing direct evidence of an unusual transannular interaction between the carbonyl group and the bridging bond.