aThe hydroformylation of 1-butene catalyzed by RhIJacac)IJCO) 2 with an excess of N-pyrrolylphosphine ligands, L = PIJNC 4 H 4 ) 3 , PPh 2 IJNC 4 H 4 ) or PPhIJNC 4 H 4 ) 2 , was investigated under constant pressure of synthesis gas (4-10 bar, H 2 /CO = 1) and 2 bar of 1-butene at temperatures ranging from 50 to 80°C.N-Pyrrolylphosphine ligands facilitated excellent selectivity towards aldehydes and regioselectivity towards linear aldehydes. The application of a higher temperature, the presence of a small amount of water, and a[L]/[Rh] ratio of ca. 13 resulted in the achievement of the highest n/iso values in a short time. A further increase in selectivity was achieved after the addition of water to the reaction mixture. The catalytic performance of the studied systems showed an increase in selectivity (n/iso) with the increase of the number of pyrrolyl groups in phosphine: (PIJNC 4 H 4 ) 3 > PPhIJNC 4 H 4 ) 2 > PPh 2 IJNC 4 H 4 )) > PPh 3 .

The hydroformylation of propene catalyzed by Rh(acac)(CO)2 (acac=acetylacetonate) with a 13‐fold excess of N‐pyrrolylphosphine ligands PPyr3, PPh2Pyr, or PPh(Pyr)2 (Pyr=NC4H4) was investigated under a pressure of 15 bar (propene/H2/CO=5:5:5) at 80 °C. The N‐pyrrolylphosphine ligands facilitated an excellent regioselectivity towards n‐butanal aldehyde, significantly better than PPh3 and PCy3 under the same conditions. In the presence of the strongest π‐acceptor, PPyr3, the linear‐to‐branched aldehyde (l/b) ratio was 8.6, which increased to 27.1 if water was added to the system. The application of a pure aldehyde as a solvent instead of toluene caused a significant increase in the aldehyde yield but with a decreased l/b ratio (2.9–7.6). The regioselectivity parameter l/b increased to 19.3 after the introduction of water as a cosolvent.

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