| 释义 |
ylid Chem.|ˈɪlɪd|
Also ylide |-aɪd|.
[a. G. ylid (Wittig & Felletschin 1944, in Ann. d. Chem. DLV. 133): see -yl, -id4.]
Any neutral compound containing a negatively charged carbon atom directly bonded to a positively charged atom of another element (commonly sulphur, phosphorus, or nitrogen). Hence yˈlidic a.
1951Chem. Abstr. XLV. 6166 The reaction of PhLi upon suitable quaternary ammonium salts results in compds. with a semipolar bond between N and adjacent C. These compds. are called ylides. 1970Nature 25 July 335/2 Silylated ylides of phosphorus, arsenic and sulphur, in which the silyl group is both a stabilizing and an efficient leaving group, transferring the ylidic moiety in very mild conditions. 1972S. J. Weininger Contemporary Org. Chem. xviii. 491 Ylids are extremely useful reactive intermediates for syntheses and are the subject of a good deal of research effort at the present time. 1979Nature 15 Nov. 231/3 The zwitterionic ylides were obtained from the reaction of phenyl-lithium with quaternary ammonium halides. 1982Heterocycles XIX. 1849 Cycloimmonium ylides..possessing two electron⁓withdrawing groups covalently bonded to the ylidic carbon..can be isolated. |