THE ROLE OF 2-DIMENSIONAL NUCLEAR-MAGNETIC-RESONANCE SPECTROSCOPY IN COMPUTER-ENHANCED STRUCTURE ELUCIDATION

Two-dimensional NMR spectroscopy is a powerful structural probe, but often in structure elucidation some of the most significant information derived therefrom - long-range carbon-hydrogen signal correlations - is more commonly used to distinguish between proposed alternatives later in the process than to construct compatible structures very early in the process. It is the uncertainty about the number of intervening bonds between correlated atoms that introduces substantial overall ambiguity in a set of such correlations and complicates their interpretation. A strategy linking a versatile, computer-based procedure for the interpretation of 2-D NMR-derived signal correlations (INFER2D) to a recently developed, structure-reduction-based structure generator (COCOA) is described which has demonstrated considerable promise in prospectively utilizing such ambiguous data in directly constructing compatible molecules, even in the presence of molecular symmetry. The software, although at a early stage of development, already possesses some problem-solving capabilities which are illustrated with several examples. Current program scope and limitations are described.