ChemInform Abstract: Two‐Directional Synthesis of Polycyclopropanes. An Approach to the Quinquecyclopropane Fragment of U‐106305.

Abstract

Two-Directional Synthesis of Polycyclopropanes. An Approach to the Quinquecyclopropane Fragment of U-106305.-It is demonstrated that two-directional stereoselective cyclopropanation is efficient for the preparation of the sym tercyclopropanes (VIII) and (IX). The nonsym compound (XIII) is prepared by an iterative one-directional application of the same reagent-mediated cyclopropanation method. The C2-sym quinquecyclopropane (XV), possessing repeating trans-sym structure, is obtained by iterative application of the two-directional strategy. It is shown that the reagent-controlled transformations are far more effective for the stereoselective preparation of the tercyclopropanes than are the reactions, which are based on the influence of the substrate stereocenters. -(MCDONALD, W. S.; VERBICKY, C. A.; ZERCHER, C. K.; J.