SYNTHESIS AND STRUCTURE OF ALLENYL-SUBSTITUTED ETA(6)-BENZENE(TRICARBONYL)CHROMIUM COMPLEXES

The Cr(CO)(3)-complexed eta(6)-phenylpropargylic alcohols 3 react in a displacement rearrangement with thionyl chloride or chlorodiphenylpho sphane to give the chloro- or phosphorylallenyl substituted eta(6)-phe nyl complexes 4 and 6, respectively. In the X-ray crystal structure of the novel organometallic allenic derivatives 4b and 6b the vicinal ch loro or phosphoryl substituent and the benzene(tricarbonyl) chromium f ragment are arranged coplanarily. Palladium/coppes-catalyzed couplings of the chloroallene 4b with terminal alkynes disclose a facile access to ynallene derivatives 8, novel carbon-rich organometallic pi-system s.