A New Diphosphite Promoting Highly Regioselective Rhodium-Catalyzed Hydroformylation

Abstract

A new rhodium catalyst is described that gives 99% regioselectivity in linear aldehyde in the hydroformylation of internal and terminal olefins. High-pressure NMR spectroscopic data verify an energetically preferred bis-equatorial mode of coordination for the bidentate phosphite ligand in the hydride resting state of the catalyst. Experimental FTIR spectra are compared with the individual spectra of the e,e and e,a isomers of [HRh(CO)2(P∩P)] calculated from density functional theory.

VIBRATIONAL SCALING FACTORS FOR Rh(I) CARBONYL COMPOUNDS IN HOMOGENEOUS CATALYSIS

“…For small molecules, the calculation of accurate anharmonic force fields is a practical option, see for example [42], but this becomes not feasible for larger molecules. For Ni(CO) 4 , for example, the estimated anharmonicity constants from isotope experiments are between -3 and -11 cm -1 [43] and would bring calculated frequencies in even closer agreement with experiments. The use of a simple vibrational scaling factor aims to correct for (i) inherent deficiencies of the electronic structure methods, and (ii) the potential energy surface to be not harmonic.…”

“…The results are summarized in Table 2. The root mean squared error (RMSE) for both of the methods is calculated as a single measure of accuracy according to Equation (4). The values for the RMSE before and after scaling are presented along with the scaling factors in Table 2.…”

“…Also being generally less sensitive to sulfur compounds and oxidizing agents, bulky aryl diphosphites are the first choice for selective production of large quantities of n-aldehydes. Phosphite ligands, such as BiPhePhos, provide 98-99% n-selectivity [4]. The ligand BiPhePhos and Rh(I)BiPhePhos precatalyst with two carbonyl and one hydride ligand are shown in Figure 1.…”

n‐butane carbonylation to n‐pentanal using a cascade reaction of dehydrogenation and SILP‐catalyzed hydroformylation

“…The BzP ligands were synthesized according to the literature. 23 The C for 24 h. CO (99.97%), H 2 (99.999%), and n-butane (99.5%) were purchased from Linde AG.…”

Applications of Rhodium-Catalyzed Hydroformylation in the Pharmaceutical, Agrochemical, and Fragrance Industries

“…Realistically, for more complex targets, any synthetic method must compete with a variety of other synthetic disconnections on factors such as cost, complexity, and waste treatment. A significant advantage of hydroformylation is perfect atom economy, and ligands developed within the past 20 years offer excellent regioselectivity [2][3][4], chemoselectivity, and functional group tolerance. For example, xantphos and biphephos ligands lead to high selectivity for linear aldehydes from terminal alkenes (Fig.…”