654085-40-2Relevant academic research and scientific papers
Synthesis of new o-alkyl substituted arylalkylphosphanes: Study of their molecular structure and influence on rhodium-catalyzed propene and 1-hexene hydroformylation
Riihimaeki, Helena,Kangas, Teija,Suomalainen, Pekka,Reinius, Heidi K.,Jaeaeskelaeinen, Sirpa,Haukka, Matti,Krause,Pakkanen, Tapani A.,Pursiainen, Jouni T.
, p. 81 - 94 (2003)
A novel set of new phosphane ligands designed to increase the branched/normal ratio of the hydroformylation reaction were prepared in the same way as the previously reported ortho-alkyl substituted arylphosphanes, which have shown increased i/n ratios in the hydroformylation of propylene and 1-hexene. To determine the relationship between the catalytic behavior and stemoelectronic characteristics of the ligands, various functional alkyl groups (methyl, isopropyl, cyclohexyl) were placed on the phosphorus atom directly and in the ortho position of the phenyl ring connected to phosphorus. In the hydroformylation reaction of propylene and 1-hexene a higher i/n ratio lead to nearly all the ligands compared with that of triphenylphosphane. As the ortho-alkyl-substituent became larger, it had a favorable effect on the i-selectivity. The o-alkyl-substituent was orientated outside the ligands' cone angle in the X-ray crystal structures of (2-cyclohexylphenyl)dicyclohexylphosphane and (2,5-dimethylphenyl)bis(4-pyridyl)phosphane, and Rh(acac)(CO)(PR3) complex of (2-methylphenyl)dicyclohexylphosphane.
