Diastereocontrolled synthesis of cis-olefins by selective C-C bond formation between alkyl and alkynyl groups coordinated to "Ir (CH=CHPPh3)(CO)(PPh3)2"

cis,cis-1,4-Dipropenylbenzene (cis,cis-p-C6H4(CH=CHCH3)2, cis-DPB) and cis,cis,cis-1,3,5-tripropenylbenzene (cis,cis,cis-m,m-C6H3 (CH=CHCH3)3, cis-TPB) are obtained in high yields by reactions of di- and tri-nuclear alkyl-alkenyl-alkynyl iridium(III) compounds, [pC6H4(C(identical)C-Ir(CH3)(CH=CHPPh3)(CO)(PPh3)2)2]2+1 and [m,m-C6H3(C(identical)C-Ir(CH3)(CH=CHPPh3)(CO)(PPh3)2)3]3+3 with HCl. The reaction of the mono-nuclear alkyl-alkenyl-alkynyl iridium(III) complex, [Ir(CH3)(CH=CHPPh3)(C(identical)C-p-C6H4CH3)(CO) (PPh3)2]+7a with DCl selectively gives cis-CD3CD=CD(p-C6H4CH3)8a-d5 while two isomers, cis-C6H5CD2CD=CD(p-C6H4CH3)8b-d4 and cis-C6H5CD=CDCD2(p-C6H4CH3)8bʹ-d4 are obtained from the reaction of [Ir(CH2Ph)(CH=CHPPh3)(C=C-p-C6H4CH3)(CO)(PPh3)2] +7b with DCl. Plausible reaction pathways containing the initial attack of H+ on the (beta)-carbon of the alkynyl ligands to produce cis -alkenyl complexes that give (eta)2-allene complexes are suggested for the selective and diastereocontrolled C-C bond forming reactions between alkyl and alkynyl groups to give cis-olefins, 8, cis-DPB, and cis-TPB.