Conformations of Six-membered Carbon Rings with Planar Groups

A systematic account is given of experimental and theoretical data on the steric structures of six-membered rings containing groups with a coplanar disposition of three consecutive bonds within the ring – a fragment with a double bond, a condensed rigid ring, or a bridged bicyclic system. We shall consider rings containing one such fragment, namely cyclohexane, bicyclo[4.1.0]heptane, and its analogues, as well as rings with two fragments of this kind in the 1,4- or 1,3-positions. Data are presented on the structure of the rings, their inversion, and the orientation of the substituents in various positions. The principal characteristics of the conformational structures of such compounds are described and the possibility of the assumption of the boat form and the relative preferences for the axial and pseudoaxial orientations of the substituents and the condensed planarising fragments are discussed.
The bibliography includes 272 references.