Carbon−Carbon Bond Formation between Adjacent Alkenyl Ligands: η3-Allyl Iridium(III) and η4-Butadiene Iridium(I) Complexes from a cis-Bis(alkenyl) Iridium(III) Complex
摘要:
A carbon-carbon bond is formed between the a-carbons of the alkenyl ligands of the cis-bis(ethenyl)iridium complex [Ir(-CH=CH2)(2)(CH3CN)(2)(PPh3)(2)](+) (2) to produce the eta(3)-allyl complex [Ir(eta(3)-CH3CHCHCH2)(NCCH3)(2)(PPh3)(2)](2+) (4) in the reaction of 2 with H+, and eta(4)- butadiene complexes Ir(eta(4)-CH2=CHCH=CH2)(A)(PPh3)(2) (A = -CH=CH-+NEt3 (6), -Cequivalent to CR (7)) in reactions of 2 with terminal alkynes (RCequivalent toCH; R = H, Ph, and p-C6H4CH3) in the presence of NEt3. The deuterium labeling experiments suggest an initial attack of H+ on the beta-carbon of an ethenyl ligand to lead to the C-C bond formation between the alpha-carbons of the two alkenyl groups of 2 to produce 4.
1,1-Insertion of substituted alkynes into the Ir–O bond of η2-carboxylato iridium complexes
作者:Chong Shik Chin、Hyungeui Lee、Myung Ki Lee、Soyoung Noh、Min-Sik Eum、Seunggweon Hong
DOI:10.1016/j.jorganchem.2004.11.040
日期:2005.3
Alkyl-carbonyl-iridium [Ir(CH3)(CO)(eta(2) - O2CR ')(PPh3)(2)](+) (1, R ' = CH3, Ph, p-C6H4CH3) react with alkynes (RC &3bond; CH; R = Ph, p-C6H4CH3) in the presence of NEt3 to give acyl-alkynyl-iridium Ir(C(=O)CH3)(-C &3bond; CR)(eta(2) -O2CR ')(PPh3)(2) (4) which further react with RC &3bond; CH to give alkyl-carbonyl-cis-bis(alkynyl) iridium Ir(CH3)(CO)(C &3bond; CR)(2)(PPh3)(2) (5). cis-Bis(alkenyl)iridium complexes, Ir(-CH=CH2)(2)(eta(2) -O2CCH3)(PPh3)(2) (6) and Ir(-CH=CHCH=CH)(eta(2)-O2CCH3)PPh3)(2) (7) react with substituted alkynes RC &3bond; CH (R = Ph, p-C6H4CH3, cyclohex-1-enyl) to give cis-bis(alkynyl) Ir(C &3bond; CR)(2)(eta(2)-O2CCH2)(PPh3)(2) (9) that further react with RC &3bond; CH to undergo the alkyne insertion reaction into the Ir-O bond to produce iridacycles containing vinyl acetate ligands, Ir(C(=CHR)OC(CH3)=O)(-C &3bond; CR)(2)(PPh3)(2) (8). (c) 2004 Elsevier B.V. All rights reserved.