ISSN:
0009-2940
Keywords:
Cyclopropenylium compounds
;
Methylenecyclopropenes
;
Isonitrile insertion
;
Methylenecyclobutenone imine derivatives
;
Cyclopropenylioborate betaines
;
C-C coupling
;
Zirconium
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Bis(propynyl)zirconocene was treated with B(C6F.5)3 and then with two equivalents of tert-butyl isocyanide to yield the organometallic three-membered ring product 8. Subsequent hydrolysis gives the substituted (2-iminioethylidene)cyclopropeneborate betaine system 9 that exhibits a pronounced cyclopropenylioborate betaine character. This follows from its characteristic structural features (X-ray crystal-structure analysis of the isomer cis-9) and its chemical features. Complex 9 undergoes a very facile cis/trans isomerization by formal rotation around the exocyclic partial CC-double bond (ΔG+ ≈ 17 kcal mol-1). Compound 9 reacts cleanly in methanol solution with tert-butyl isocyanide by insertion and ring enlargement to form the four-membered ring system 12. Compound 12 was also characterized by X-ray diffraction.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19971300809
