C-H BOND ACTIVATION BY RHODIUM(I) AND THE MECHANISM OF THE OLEFIN ISOMERIZATION - NEW SYNTHESIS OF BETA,GAMMA-UNSATURATED KETONES VIA ETA-1-ALKYLALLYLRHODIUM(III) OR ETA-3-ALKYLALLYLRHODIUM(III) COMPLEXES BY REDUCTIVE ELIMINATION

Acylrhodium(III)-η3-1-ethylallyl complex (7) was prepared by the reaction of 8-quinolinecarboxaldehyde (3) and 1,4-pentadienerhodium(I) chloride (2) by CH bond activation, followed by hydrometallation, and double bond migration. Higher concentrations of pyridine as coordinating ligand transforms η3-1-ethylallylrhodium(III) complexes (8a,8b) into η1-pent-2-enylrhodium(III) complex (11a). Acylrhodium(III)-η3-syn,anti-1,3-dimethylallyl complex (14) was also prepared from 1,3-pentadienerhodium(I) chloride (16) and 3. The reductive elimination of acylrhodium(III)-η1- and -η3-1-alkylallyl complexes by trimethylphosphite gives various β,γ-unsaturated ketones. © 1990.