STERIC AND STEREOELECTRONIC EFFECTS IN SATURATED HETEROCYCLES .1. SMALL MOLECULAR FRAGMENT CONSTITUENTS - THEORY VS EXPERIMENT

Structural and energetic consequences of replacing one or more carbon atoms in small, cyclic and acyclic hydrocarbons with electronegative a toms or groups are reviewed. In this first part, the conformation-depe ndent steric and stereoelectronic effects on the properties (energies, structural parameters, etc.) of small molecular building blocks are s crutinized and these molecules are then used in a ''fragment analysis' ' of lar er molecules, such as carbohydrates or other mono- and polyhe terocycles. Satisfactory results were obtained for molecules with sing le and multiple instances of anomeric and gauche effects involving O a nd N heteroatoms. (C) 1997 Elsevier Science B.V.