Symmetrizing the unsymmetrical

摘要

You might think that the partial symmetry of the molecule complanadine A makes it easy to prepare, but the reverse is true. Two syntheses of this compound offer insight into how to make partly symmetrical molecules. When the molecular structures of naturally occurring organic compounds are symmetrical, it is relatively easy for synthetic chemists to come up with a blueprint to make them in the laboratory. But if that symmetry is broken just a little- say, by the presence of a single bond in the 'wrong' place, or by the insertion of an atom into one of the two otherwise equivalent parts of the molecule- then all bets are off. Two recent syntheses of the non-symmetrical molecule (+)-complanadine A, reported in the Journal of the American Chemical Society, provide insight into how to access such non-symmetrical structures. Ironically, the key to success involves symmetry.