释义 |
sigmatropic, a. Chem.|sɪgməˈtrɒpɪk| [f. sigma + -tropic.] Involving the movement of a sigma bond to a new pair of atoms within a molecule.
1965Woodward & Hoffmann in Jrnl. Amer. Chem. Soc. LXXXVII. 2511/2 We define as a sigmatropic change of order [i, j] the migration of a σ-bond, flanked by one or more π-electron systems, to a new position whose termini are i{b1}1 and j{b1}1 atoms removed from the original bonded loci, in an uncatalyzed intramolecular process. 1974Gill & Willis Pericyclic Reactions iii. 84 The transition state of a sigmatropic change is..reminiscent of the transition state of a cyclo-addition reaction. |