SYMMETRY GUIDELINES FOR THE DESIGN OF CONVERGENT SYNTHESES - ON NARCISSISTIC COUPLING AND LA-COUPE-DU-ROI

A symmetry point group study of different segmentation patterns for molecules is presented as an aid for their retrosynthetic analysis. Symmetry properties of the target molecule allow the design of synthetic routes using either achiral, homochiral, or heterochiral isometric segments. It is found that chiral molecules can only be dissected into homochiral segments, whereas achiral molecules can only be fragmented into achiral or heterochiral segments in most cases. The only achiral molecules which can be dissected into homochiral segments (la coupe du roi) are those belonging to the C(nv) or D(nd) point groups, in two particular dissection modes.